Hot plug expansion system and method of non-hot plug display interface

Abstract

The invention provides a hot-plug expansion system and method for a non-hot-plug display interface, and relates to the technical field of display interface detection, and the system comprises a display screen end expansion circuit, a processor end expansion circuit and a drive program module. The display screen end expansion circuit comprises a first pin and a flash memory chip for storing display parameters; the processor end expansion circuit comprises a second pin and a host interface; the drive program module comprises an interrupt processing unit, a parameter reading unit and a display control unit. According to the method, hot plug function support is added for a traditional non-hot plug display interface through minimum hardware extension, dynamic self-adaptive configuration of display parameters is achieved, the technical problems that the interface lacks a native plug detection mechanism and cannot dynamically adapt to the display parameters are solved, and the method has the advantages of being low in cost, good in compatibility and high in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of display interface detection, and in particular to a hot-plug expansion system and method for a non-hot-plug display interface. Background Art

[0002] Among different display interfaces, modern interfaces like HDMI and DisplayPort were designed with hot-plug functionality in mind. For example, the HDMI standard includes a dedicated HPD (Hot Plug Detect) pin for detecting the display device's connection status. When a display device is connected or disconnected, the voltage level on the HPD pin changes. By detecting this change, the system can detect the device's connection status in real time and take appropriate action. HDMI also reads the display device's EDID (Extended Display Identification Data) information through the DDC (Display Data Channel) to obtain parameters such as the display's resolution and refresh rate, enabling automatic configuration of display parameters.

[0003] However, traditional display interfaces, such as RGB and MIPI-DSI, were not designed with hot-swap functionality in mind. These interfaces are primarily used in embedded systems, industrial control, and medical equipment. In these applications, displays are typically permanently connected during system integration and rarely require hot-swap operation during runtime. Consequently, these interfaces lack dedicated hot-swap detection pins in their hardware designs and corresponding software support mechanisms.

[0004] As application requirements evolve, more and more scenarios require hot-swap support for traditional interfaces like RGB and MIPI-DSI. For example, during industrial equipment maintenance, technicians may need to temporarily connect a display screen for parameter adjustment; in medical equipment, different display specifications may need to be switched to suit different usage scenarios; and in multimedia presentation systems, flexible switching between different display devices is required. In these application scenarios, the lack of hot-swap support for traditional display interfaces creates numerous inconveniences.

[0005] Specifically, existing non-pluggable interfaces such as RGB and MIPI-DSI have the following technical problems: First, these interfaces lack physical plug-in and unplug detection mechanisms. Without dedicated detection pins in the hardware, the system cannot directly detect when a display is connected or disconnected. This means that display functionality must be statically initialized at system startup. Once the system is running, display devices cannot be dynamically added or removed. Forcibly plugging or unplugging a display while the system is running can cause system anomalies, display distortion, or even hardware damage.

[0006] Secondly, these interfaces lack the ability to adapt to dynamic display parameters. Existing solutions typically rely on preset fixed resolution and timing parameters, which are determined at system startup and cannot be dynamically adjusted based on the actual connected display parameters. When the connected display parameters do not match the preset parameters, problems such as black screen, distorted screen, and display anomalies may occur, seriously affecting the user experience. In actual applications, technicians often need to manually modify configuration files, recompile drivers, and even restart the system to adapt to the new display, which is complex and inefficient.

[0007] Thirdly, display screens produced by different manufacturers have different parameter formats, and existing parameter reading solutions lack a unified standard. Even if display parameters are obtained through some means, they may not be correctly parsed due to format incompatibility. These cross-platform and cross-device compatibility issues increase the complexity of system integration, requiring customized adaptation for different manufacturers' products, significantly increasing development costs and maintenance difficulties.

[0008] Furthermore, at the software level, the existing display driver framework doesn't provide hot-plugging support for these legacy interfaces. While the Linux kernel's DRM (DirectRenderingManager) subsystem provides a comprehensive display management framework, its event handling mechanisms don't function properly for interfaces without hardware hot-plugging detection. Consequently, even if a display plug-in or unplugging event is detected, it can't be properly relayed to userspace, preventing the desktop environment from responding appropriately.

[0009] Chinese patent document CN113099552A discloses a pluggable device and a screen transmission method, and discloses a technical solution for realizing wireless screen transmission function through an independent pluggable device. This solution integrates a network module, a driver module and a hardware interface in the pluggable device, so that the screen transmission function is no longer limited by the network architecture design of the receiving device, thereby enhancing the device's screen transmission capability and improving the flexibility of the screen transmission function. However, it still does not solve the fundamental problem that traditional display interfaces (such as RGB, MIPI-DSI, etc.) themselves do not support hot-swap functions. In essence, it provides a wireless transmission solution at the application layer, rather than realizing hot-swap support for the display interface from the underlying driver and hardware level.

[0010] Chinese patent document CN117055966A discloses a hot-plug detection and processing method, device and storage medium based on HDMI, and discloses a technical solution for optimizing the HDMI hot-plug detection logic by comprehensively judging the HPD signal and EDID information. By improving the detection process and adding a retry mechanism, this solution solves the problem of desktop screen flickering caused by voltage level jitter during the hot-plug process of some displays, and has the technical effect of improving the hot-plug stability of the HDMI interface and improving the user experience. However, it still does not solve the problem of how traditional display interfaces such as RGB and MIPI-DSI that do not originally have the hardware basis for hot-plug detection can achieve hot-plug functions. This solution is only applicable to HDMI interfaces that already have HPD pins and cannot be extended to other types of display interfaces.

[0011] In summary, traditional display interfaces like RGB and MIPI-DSI have significant technical deficiencies in hot-swap support, severely limiting their flexibility in modern applications. Adding hot-swap functionality to these traditional interfaces, enabling them to dynamically connect and disconnect display devices like modern interfaces like HDMI and automatically identify and configure display parameters, has become a pressing technical challenge in this field. Summary of the Invention

[0012] The object of the present invention is to provide a hot-plug expansion system and method for a non-hot-plug display interface that realizes the hot-plug function of a traditional display interface by minimizing hardware expansion and supports dynamic adaptive configuration of display parameters.

[0013] To achieve the above object, the present invention is implemented through the following technical solutions: A hot-swap expansion system for a non-hot-swap display interface includes a display screen and a host, the display screen and the host are connected, the display screen is provided with a non-hot-swap display interface, and further includes a display screen end expansion circuit, a processor end expansion circuit and a driver module; The display screen end expansion circuit is provided on the display screen driver board, and includes a first pin and a flash memory chip, and the flash memory chip is connected to the display screen driver board; The processor-side expansion circuit is provided on the processor side of the host, and includes a second pin and a host interface, wherein the host interface is connected to the flash memory chip; the second pin is connected to the first pin; The driver module runs in the operating system kernel of the processor and includes: an interrupt processing unit, configured to respond to a level change of the second pin and trigger an interrupt service routine when detecting that the display screen is pulled out; A parameter reading unit, configured to read the display screen parameters through the host interface when detecting that the display screen is inserted; The display control unit is used to dynamically initialize the display controller module in the CPU according to the read display screen parameters.

[0014] Furthermore: the flash memory chip is connected to the display screen driver board via an I2C bus.

[0015] Furthermore: the first pin and the second pin are both GPIO pins.

[0016] Furthermore: the display screen parameters include resolution information and timing parameters.

[0017] Furthermore, the flash memory chip stores multiple copies of the same display screen parameter data, and the flash memory chip also stores a data accumulation value and a cyclic redundancy check value.

[0018] Furthermore, the driver module further includes an event notification unit, which sends a notification to the user space through the uevent mechanism or the sysfs file system after detecting the display screen plugging and unplugging event.

[0019] Furthermore: the non-hot-plug display interface is an RGB interface or a MIPI-DSI interface.

[0020] A method for detecting a hot-plug expansion system of a non-hot-plug display interface comprises the following steps: S1: monitors the level status of the pins of the non-hot-swappable display interface; S2: When a change in the pin level is detected, the interrupt service routine of the interrupt processing unit is triggered; S3: In the interrupt service program, the level change type is determined. If it is a high level, it is determined that the display screen is inserted; if it is a low level, it is determined that the display screen is unplugged; S4: When it is determined that the display screen is inserted, the display parameters in the display screen flash memory are read through the interface and verified. If the verification passes, the display controller module in the CPU is initialized with the parameters; when it is determined that the display screen is unplugged, the display parameter resources are released and the display controller module in the CPU is turned off.

[0021] Furthermore, the process of reading and verifying the display parameters in step S4 specifically includes: S41: Read two copies of display parameter data in the flash memory and compare whether the two copies of data are consistent; S42: Calculate the cumulative sum of the data and the cyclic redundancy check value. If the data is consistent and the check passes, confirm that the parameter is valid; if the data is inconsistent or the check fails, reread.

[0022] Furthermore, in step S4, after verifying the read display parameters, the method further includes: calling the kernel's drm_helper_hpd_irq_event function to report the display screen insertion status.

[0023] Compared with the prior art, the present invention has the following beneficial effects: First, this invention successfully implements hot-swap functionality for traditional non-hot-swap display interfaces such as RGB and MIPI-DSI. By adding pins and a flash memory chip to the display, and corresponding pins and a host interface to the processor, along with a specially designed driver, this enables display interfaces that previously could only be statically initialized at system startup to support dynamic plug-in and unplugging operations at runtime, fundamentally resolving the technical challenge of these interfaces lacking a native plug-in detection mechanism.

[0024] Second, the present invention enables dynamic, adaptive configuration of display parameters. When a display screen is plugged in, the system automatically reads parameters such as resolution and timing stored in flash memory and dynamically initializes the display controller module in the CPU based on these parameters, without requiring manual intervention or driver recompilation. When connecting displays of varying specifications, the system automatically identifies and configures the corresponding display parameters, completely resolving the problem of existing solutions relying on preset fixed parameters and being unable to adapt to different displays. This significantly improves the system's flexibility and ease of use.

[0025] Third, this invention provides a universal solution across platforms and manufacturers. It utilizes standardized hardware interfaces (GPIO, I2C / SPI) and a software design framework, independent of vendor-specific proprietary technologies, resulting in excellent versatility and portability. By employing a unified parameter storage format in flash memory and combining it with a comprehensive data verification mechanism, it effectively resolves compatibility issues arising from differences in EDID data formats across different manufacturers' displays, significantly reducing the costs of system integration and customized adaptation.

[0026] Fourth, the present invention requires minimal hardware modifications and is cost-effective. The entire expansion solution requires only the addition of a small number of low-cost components to the existing hardware, such as GPIO pins, an I2C interface, and a small-capacity flash memory chip. No modifications are required to the existing display interface protocol, ensuring full compatibility with existing systems. This minimal modification approach gives the present invention significant practical value and potential for widespread adoption.

[0027] Fifth, the system provided by the present invention is highly reliable. By storing two identical copies of parameter data in flash memory and employing a dual verification mechanism of cumulative sum and cyclic redundancy check, the accuracy and reliability of parameter reading are ensured, effectively preventing display anomalies caused by data corruption or transmission errors. Furthermore, the event notification mechanism provided by the present invention enables accurate response to plug-in and unplug events from the underlying hardware to upper-layer applications, ensuring stable operation of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic structural diagram of a hot-swap expansion system for a non-hot-swap display interface provided by the present invention; Figure 2 The present invention provides a flow chart of a method for detecting a hot-plug expansion system of a non-hot-plug display interface. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] Example 1 like Figure 1 As shown, the present invention provides a hot-swap expansion system for a non-hot-swap display interface. The system mainly includes a display screen, a host, a display-side expansion circuit, a processor-side expansion circuit, and a driver module. The display screen and the host are connected via a non-hot-swap display interface, such as an RGB interface or a MIPI-DSI interface. These interfaces do not support hot-swap functionality in traditional designs. This embodiment adds hot-swap capability to them through hardware expansion and software coordination.

[0031] The display expansion circuit is located on the display driver board and primarily consists of a first pin and a flash memory chip. When the display is inserted or removed, the voltage level on the first pin changes accordingly. The flash memory chip stores key display parameters, including resolution, refresh rate, pixel clock, and horizontal and vertical synchronization timing. The flash memory chip connects to the display driver board via a standard interface, allowing the processor to read these parameters.

[0032] The processor-side expansion circuit is located on the host processor side and includes a second pin and a host interface. The second pin is connected to the first pin on the display screen and is used to receive the display screen's plug-in and unplug status signal. When the display screen is plugged in, the first pin outputs a high level, which is detected by the second pin. When the display screen is unplugged, the first pin outputs a low level, which is detected by the second pin. The host interface is connected to the flash memory chip on the display screen and is responsible for reading the display parameters stored in the flash memory.

[0033] The driver module runs in the processor's operating system kernel and is the core software component that implements the hot-swap function. This module includes three main functional units. The interrupt processing unit is responsible for monitoring the level changes of the second pin. When a level change is detected, it triggers the corresponding interrupt service routine. The interrupt service routine determines whether it is an insertion event or an unplug event based on the level. The parameter reading unit is activated after detecting the display screen insertion event. It communicates with the flash memory chip on the display screen end through the host interface to read the stored display parameters. The display control unit dynamically configures the display controller module in the CPU based on the read parameters, including setting the resolution, refresh rate, timing parameters, etc., so that the display screen can work normally.

[0034] In one specific implementation of this embodiment, the flash memory chip is connected to the display driver board via an I2C bus. The I2C bus is a widely used serial communication interface with the advantages of simple connection and low pin count. Through the I2C bus, the processor can easily read data from the flash memory. The flash memory chip acts as an I2C slave device with a fixed device address. The processor acts as an I2C master device, acquiring display parameters by sending read commands and address information.

[0035] In one specific implementation of this embodiment, both the first and second pins are implemented as GPIO pins. GPIO pins have flexible configuration features and can be set to input or output mode, supporting interrupt functionality. On the display side, the first pin is configured in output mode, outputting a corresponding voltage level based on the display's connection status. On the processor side, the second pin is configured in input mode with the interrupt function enabled. This allows for immediate triggering of an interrupt service routine upon voltage level changes, enabling rapid response.

[0036] In a specific implementation of this embodiment, display screen parameters include resolution information and timing parameters. Resolution information includes the number of horizontal pixels and vertical pixels, such as 1920×1080 and 1280×720. Timing parameters include pixel clock frequency, horizontal sync pulse width, horizontal back porch, horizontal active period, horizontal front porch, vertical sync pulse width, vertical back porch, vertical active period, and vertical front porch. These parameters are crucial for correctly driving the display screen; errors in any of these parameters may cause display abnormalities.

[0037] In one specific implementation of this embodiment, to improve data reliability, two identical copies of display parameter data are stored in the flash memory chip. This redundant storage method effectively prevents parameter errors caused by flash memory damage or data bit flipping. The flash memory also stores the accumulated data sum and a cyclic redundancy check value. When the processor reads the parameters, it first compares the two copies of data for consistency. It then calculates the accumulated sum and the cyclic redundancy check value. Only if the data is consistent and the check passes is the parameter considered valid. If the data is inconsistent or the check fails, the system attempts to reread to ensure the correct parameters.

[0038] In a specific implementation of this embodiment, the driver module also includes an event notification unit. After detecting the display screen plug-in and unplug event, this unit is responsible for passing the event information to the application in the user space. Event notification adopts the standard mechanism of the Linux system, including the uevent mechanism and the sysfs file system. Through the uevent mechanism, the kernel can broadcast hot plug events to the user space, and the desktop management program running in the user space can monitor these events and make corresponding processing, such as reconfiguring the display layout, adjusting the resolution, etc. Through the sysfs file system, the user space program can actively query the connection status and parameter information of the display screen.

[0039] In a specific implementation of this embodiment, the non-hot-swappable display interface can be an RGB interface or a MIPI-DSI interface. The RGB interface is a parallel display interface widely used in embedded systems and industrial control fields. The MIPI-DSI interface is a display serial interface standard developed by the Mobile Industry Processor Interface Alliance and is mainly used in mobile devices and embedded systems. Neither of these two interfaces supports hot-swappable functionality in their original designs. Through the expansion solution of this embodiment, they can obtain hot-swappable capabilities similar to modern interfaces such as HDMI.

[0040] Example 2 like Figure 2 As shown, the present invention also provides a method for detecting a hot-plug expansion system of a non-hot-plug display interface, which includes the following steps.

[0041] First, the system continuously monitors the pin status of the non-hot-pluggable display interface. This monitoring is accomplished using a second pin on the processor, configured as an input with interrupt functionality enabled. Under normal operating conditions, the system is in a low-power wait state, eliminating the need for active pin polling.

[0042] When the display is plugged in or out, the voltage level on pin 1 changes, and this change is transmitted to pin 2 via the connecting wire. Upon detecting the voltage change, pin 2 immediately generates an interrupt request. Upon receiving the interrupt request, the processor pauses the currently executing program and executes the pre-registered interrupt service routine.

[0043] In the interrupt service routine, the current level of pin 2 is read to determine the type of level change. If a high level is detected, the display has just been plugged in; if a low level is detected, it has just been unplugged. This judgment process requires consideration of level stability to avoid misjudgments due to poor contact or electromagnetic interference.

[0044] When a display insertion event is detected, the system initiates the parameter reading process. Through the host interface, the system sends a read command to the flash memory chip on the display to retrieve the stored display parameters. The reading process follows the I2C communication protocol, first sending a start signal, then the flash memory chip's device address and read command, then the address of the data to be read, and finally receiving the data returned by the flash memory. After obtaining the parameters, the system performs a rigorous verification process to ensure their correctness. If the verification passes, the system uses these parameters to initialize the display controller module in the CPU, including setting the display resolution, configuring timing parameters, and enabling display outputs. Once initialization is complete, the display can display images normally.

[0045] When a display is unplugged, the system executes a cleanup process. First, it stops outputting signals to the display interface to prevent potential hardware damage caused by outputting signals without a load. It then releases previously allocated display parameter memory resources, shuts down the relevant functional modules of the display controller module in the CPU, and returns the system to standby mode, awaiting the next insertion of a display.

[0046] According to a specific implementation of this embodiment, the system employs multiple safeguards during parameter reading and verification. First, two copies of parameter data are read from flash memory. These two copies are written to different areas of the flash memory during display manufacturing. The system compares the two copies for complete consistency. If they are, the data is intact. Next, the system calculates the cumulative sum of the read data and compares the result with the cumulative sum stored in the flash memory. The cumulative sum is a simple and effective verification method that can detect most data errors. Finally, the system calculates the cyclic redundancy check (CRC) value of the data, a more rigorous verification method that can detect error patterns that the cumulative sum cannot detect. The system considers the parameters valid only if the two copies of data are consistent, the cumulative sum is correct, and the CRC passes. If any of the verification steps fail, the system attempts to reread the data, up to three times. If all three attempts fail, the system reports an error and prompts the user to check the hardware connection.

[0047] According to a specific implementation of this embodiment, after the parameter verification is passed, the system also needs to call the kernel's display management framework function to report the hot plug event to the upper-level software. Specifically, the system calls the drm_helper_hpd_irq_event function, which is a standard interface provided by the Linux kernel DRM subsystem for handling hot plug events of display devices. By calling this function, the system can trigger a series of subsequent processes, including notifying the display manager in user space, updating the display configuration, and re-negotiating the display mode. In this way, the entire system, from the underlying hardware to the upper-level applications, can correctly respond to the plug and unplug events of the display screen, realizing complete hot plug function support.

[0048] It should be noted that, in addition to the GPIO pin detection scheme used in the above embodiment, the present invention can also employ capacitive touch detection in place of the GPIO pin detection scheme. This scheme differs from the above scheme only in the detection method. In this scheme, the system places a capacitive sensor near the display interface and uses the capacitance change caused by the plugging and unplugging process to determine the connection status. When the display interface is disconnected, the capacitive sensor detects the ambient capacitance value. When the display connector approaches or is inserted, the metal contact piece and cable change the electric field distribution around the sensor, causing a significant change in the capacitance value. The system continuously monitors the capacitance value using a dedicated capacitance detection chip. When the capacitance value exceeds a preset threshold, it is determined to be an insertion event. When the capacitance value drops below the threshold, it is determined to be an unplugging event. This solution is particularly suitable for extremely space-sensitive micro devices, such as smart watches, health monitors, and other wearable devices. Because it does not require additional GPIO pins, this solution has higher hardware compatibility and can be used in applications where pin resources are extremely limited. The capacitance detection chip communicates with the main processor via an I2C or SPI interface and reports the detection results to the driver. The subsequent parameter reading and display initialization process is the same as in the above embodiment.

[0049] It should be noted that the present invention can also use a voltage / current signal detection method to achieve hot plug sensing. This solution determines plug-in and unplug events by monitoring the voltage or current changes on the display interface power supply line. At the moment the display screen is plugged in, the sudden connection of the load will cause an instantaneous voltage drop or current surge on the power supply line; at the moment the display screen is unplugged, the load disconnection will cause the voltage to rise or the current to drop suddenly. The system connects a precision sampling resistor in series on the power supply line and collects voltage or current signals in real time through a high-speed analog-to-digital converter. When it is detected that the signal change exceeds the set threshold, the corresponding plug-in event handler is triggered. This solution is particularly suitable for high-reliability equipment in the industrial control field, such as PLC control panels, industrial human-machine interfaces, etc. In order to improve the accuracy of detection, the system needs to add appropriate filtering circuits, including hardware low-pass filters and software digital filtering algorithms, to eliminate the influence of power supply noise and other interference signals. The detection circuit can be integrated into the power management module and notify the main processor through interrupts, avoiding the power consumption problem caused by continuous polling.

[0050] It should be noted that, at the software level, the present invention can employ a hybrid detection mechanism based on polling optimization. This mechanism combines the advantages of both timed polling and interrupt-triggered detection methods. The system sets a low-frequency timer, for example, which triggers once per second, and uses the timer interrupt to check the display's connection status. Simultaneously, the system retains the GPIO interrupt detection mechanism to quickly respond to plug-in and unplug events. When a GPIO interrupt is triggered, the system temporarily increases the polling frequency, for example, checking every 10 milliseconds for the next 100 milliseconds to ensure accurate capture of changes in plug-in and unplug status. This hybrid mechanism can effectively avoid interrupt storms caused by poor connection or electromagnetic interference, preventing system resources from being exhausted by a large number of interrupt requests. This solution is particularly suitable for embedded systems with limited GPIO resources, such as MCU-based control platforms. In these systems, GPIO pins are often shared by multiple functional modules. By reducing reliance on interrupt resources, the overall system stability can be improved. The polling frequency can be dynamically adjusted based on the application scenario, increasing the frequency in applications with high real-time requirements and reducing the frequency in standby mode to save power.

[0051] It should be noted that the present invention can also employ an event-driven asynchronous reporting model. In this model, the underlying plug-in detection module encapsulates detected events into standard asynchronous messages and publishes them via the system's message bus (e.g., D-Bus on Linux or Binder on Android). Upper-level display management services, desktop environments, and applications can subscribe to these messages and process them accordingly. This design completely decouples the hardware detection layer from the business logic layer, enhancing system modularity and scalability. For example, upon receiving a plug-in event, the display management service can automatically adjust the desktop resolution and layout; media playback applications can automatically switch output modes based on the display's connection status; and the system monitoring service can log plug-in events for troubleshooting. The message format uses a standard key-value pair structure, containing information such as the event type, timestamp, device identifier, and display parameters. This asynchronous model is particularly suitable for operating systems that support event-driven architectures, such as Linux and Android, and can fully leverage the system's infrastructure, reducing development complexity and improving system maintainability.

[0052] It should be noted that the present invention can also use the SPI bus to read the display screen parameters in terms of bus protocol. Compared with the I2C bus used in the aforementioned embodiment, the SPI bus has a higher data transmission rate, which can reach tens of megabits per second or even higher. However, the use of the SPI bus also brings some challenges in hardware design. In addition to the need to add chip select signal lines, the SPI bus also has higher requirements for signal integrity. It is necessary to pay special attention to trace length matching, impedance control and signal shielding during PCB design to ensure reliable transmission of high-speed signals. At the software level, the driver needs to implement the control logic of the SPI bus, including clock frequency setting, transmission mode configuration, chip select signal management, etc., which is slightly more complicated than the implementation of the I2C bus, but still within an acceptable range.

[0053] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A hot-swappable expansion system for a non-hot-swappable display interface, comprising a display screen and a host, wherein the display screen and the host are connected, and the non-hot-swappable display interface is provided on the display screen, characterized in that: It also includes a display screen side expansion circuit, a processor side expansion circuit and a driver module; The display screen end expansion circuit is provided on the display screen driving board, and includes a first pin and a flash memory chip, and the flash memory chip is connected to the display screen driving board; The processor-side expansion circuit is provided on the processor side of the host, and includes a second pin and a host interface, and the host interface is connected to the flash memory chip; The second pin is connected to the first pin; The driver module runs in the operating system kernel of the processor and includes: An interrupt processing unit, configured to respond to a level change of the second pin and trigger an interrupt service routine when detecting that the display screen is pulled out; A parameter reading unit, configured to read the display screen parameters through the host interface when detecting that the display screen is inserted; The display control unit is used to dynamically initialize the display controller module in the CPU according to the read display screen parameters.

2. The hot-swap expansion system of a non-hot-swap display interface according to claim 1, characterized in that: The flash memory chip is connected to the display screen driving board via an I2C bus.

3. The hot-swap expansion system of a non-hot-swap display interface according to claim 1, characterized in that: The first pin and the second pin are both GPIO pins.

4. The hot-swap expansion system of a non-hot-swap display interface according to claim 1, characterized in that: The display screen parameters include resolution information and timing parameters.

5. The hot-swap expansion system of a non-hot-swap display interface according to claim 1, characterized in that: The flash memory chip stores a plurality of identical display screen parameter data, and the flash memory chip also stores a data accumulation value and a cyclic redundancy check value.

6. The hot-swap expansion system of a non-hot-swap display interface according to claim 1, characterized in that: The driver module further includes an event notification unit, which sends a notification to the user space through the uevent mechanism or the sysfs file system after detecting the display screen plugging and unplugging event.

7. The hot-swap expansion system of a non-hot-swap display interface according to claim 1, characterized in that: The non-hot-plug display interface is an RGB interface or a MIPI-DSI interface.

8. A method for detecting a hot-plug expansion system of a non-hot-plug display interface, characterized in that: The following steps are involved: S1: monitors the level status of the pins of the non-hot-swappable display interface; S2: When a change in the pin level is detected, the interrupt service routine of the interrupt processing unit is triggered; S3: In the interrupt service program, the level change type is determined. If it is a high level, it is determined that the display screen is inserted; if it is a low level, it is determined that the display screen is unplugged; S4: When it is determined that the display screen is inserted, the display parameters in the display screen flash memory are read through the interface and verified. If the verification passes, the display controller module in the CPU is initialized with the parameters; when it is determined that the display screen is unplugged, the display parameter resources are released and the display controller module in the CPU is turned off.

9. The method for detecting a hot-plug expansion system of a non-hot-plug display interface according to claim 8, wherein: The process of reading and verifying the display parameters in step S4 specifically includes: S41: Read two copies of display parameter data in the flash memory and compare whether the two copies of data are consistent; S42: Calculate the cumulative sum of the data and the cyclic redundancy check value. If the data is consistent and the check passes, confirm that the parameter is valid; if the data is inconsistent or the check fails, reread.

10. The method for detecting a hot-plug expansion system of a non-hot-plug display interface according to claim 8, wherein: In step S4, after verifying the read display parameters, the method further includes: calling the kernel's drm_helper_hpd_irq_event function to report the display screen insertion status.

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