A hot-plug expansion system and method of a non-hot-plug display interface

Abstract

The application provides a hot plug expansion system and method of a non-hot plug display interface, relates to the technical field of display interface detection, and comprises a display screen end expansion circuit, a processor end expansion circuit and a driver 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; and the driver program module comprises an interrupt processing unit, a parameter reading unit and a display control unit. The application adds hot plug function support to the traditional non-hot plug display interface through minimal hardware expansion, realizes dynamic adaptive configuration of display parameters, solves the technical problems that such interfaces lack a native plug detection mechanism and cannot dynamically adapt display parameters, and has the advantages of low cost, good compatibility and high reliability.

Description

Technical Field

[0001] This invention relates to the field of display interface testing technology, and specifically to a hot-swappable expansion system and method for a non-hot-swappable display interface. Background Technology

[0002] Among the different types of display interfaces for monitors, modern interfaces such as HDMI and DisplayPort were designed with hot-plugging functionality in mind from the outset. Taking HDMI as an example, its standard includes a dedicated HPD (HotPlug Detect) pin for detecting the connection status of the display device. When the display device is connected or disconnected, the level of the HPD pin changes. By detecting this change, the system can understand the connection status of the display device in real time and take appropriate action. Simultaneously, HDMI also reads the EDID (Extended Display Identification Data) information of the display device through the DDC (Display Data Channel) to obtain parameters such as the monitor's resolution and refresh rate, enabling automatic configuration of display parameters.

[0003] However, traditional display interfaces such as RGB and MIPI-DSI are not designed with hot-swapping functionality in mind. These interfaces are mainly used in embedded systems, industrial control, and medical equipment, where the display screen is typically fixed during system integration and rarely needs to be plugged in or unplugged during runtime. Therefore, these interfaces do not integrate dedicated hot-swapping detection pins in their hardware design and lack corresponding software support mechanisms.

[0004] As application requirements evolve, more and more scenarios necessitate hot-swapping capabilities for traditional interfaces such as RGB and MIPI-DSI. For example, in industrial equipment maintenance, technicians may need to temporarily connect a display for parameter adjustments; in medical equipment, different display sizes may need to be switched depending on the usage scenario; and in multimedia display systems, flexible switching between different display devices is required. In these application scenarios, the lack of hot-swapping support for traditional display interfaces causes numerous inconveniences.

[0005] Specifically, existing non-pluggable interfaces such as RGB and MIPI-DSI have the following technical problems:

[0006] First, these interfaces lack a physical-level plug-in / plug-out detection mechanism. Because there are no dedicated detection pins in the hardware, the system cannot directly sense whether the display is connected or disconnected. This means that the display function must be statically initialized at system startup; once the system is running, display devices cannot be dynamically added or removed. Forcibly plugging or unplugging the display while the system is running may cause system malfunctions, screen flickering, or even hardware damage.

[0007] Secondly, these interfaces lack adaptability to dynamic display parameters. Existing solutions typically rely on preset fixed resolutions and timing parameters, which are determined at system startup and cannot be dynamically adjusted based on the actual parameters of the connected display. When the parameters of the connected display do not match the preset parameters, problems such as black screens, screen distortion, and display abnormalities may occur, severely impacting the user experience. In practical applications, technicians often need to manually modify configuration files, recompile drivers, or even restart the system to adapt to new displays, which is complex and inefficient.

[0008] Secondly, displays from different manufacturers differ in 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. This cross-platform and cross-device compatibility issue increases the complexity of system integration, requiring customized adaptation for products from different manufacturers, significantly increasing development costs and maintenance difficulty.

[0009] Furthermore, at the software level, existing display driver frameworks do not provide hot-plug support for these traditional interfaces. While the Linux kernel's DRM (DirectRenderingManager) subsystem provides a comprehensive display management framework, its event handling mechanisms fail to function correctly for interfaces lacking hardware hot-plug detection capabilities. This means that even if a display plugging / unplugging event is detected in some way, it cannot be properly transmitted to user space, resulting in the desktop environment failing to respond accordingly.

[0010] Chinese patent document CN113099552A discloses a pluggable device and a screen sharing method. It discloses a technical solution for realizing wireless screen sharing function through an independent pluggable device. This solution integrates a network module, a driver module and a hardware interface into the pluggable device, so that the screen sharing function is no longer limited by the network architecture design of the receiving device. It has the technical effect of enhancing the screen sharing capability of the device and improving the flexibility of the screen sharing function. However, it still does not solve the fundamental problem that traditional display interfaces (such as RGB, MIPI-DSI, etc.) do not support hot-swapping. In essence, it provides a wireless transmission solution at the application layer, rather than realizing hot-swapping support for display interfaces from the underlying driver and hardware level.

[0011] Chinese patent document CN117055966A discloses a method, device, and storage medium for hot-plug detection and processing based on HDMI. It discloses a technical solution that optimizes the HDMI hot-plug detection logic by comprehensively judging HPD signal and EDID information. This solution solves the problem of desktop screen flickering caused by level jitter during hot-plugging of some monitors by improving the detection process and adding a retry mechanism. It has achieved the technical effect of improving the stability of HDMI interface hot-plugging and improving user experience. However, it still does not solve the problem of how traditional display interfaces such as RGB and MIPI-DSI, which do not have the original hardware foundation for hot-plug detection, can realize the hot-plug function. This solution is only applicable to HDMI interfaces that already have HPD pins and cannot be widely applied to other types of display interfaces.

[0012] In summary, traditional display interfaces such as RGB and MIPI-DSI have significant technical shortcomings in hot-swapping support, which severely limit their flexibility in modern applications. How to add hot-swapping functionality to these traditional interfaces, enabling them to support dynamic connection and disconnection of display devices like modern interfaces such as HDMI, and to achieve automatic identification and configuration of display parameters, has become a pressing technical problem to be solved in this field. Summary of the Invention

[0013] The purpose of this invention is to provide a hot-swappable expansion system and method for a non-hot-swappable display interface that achieves hot-swappable functionality of a traditional display interface by minimizing hardware expansion and supports dynamic adaptive configuration of display parameters.

[0014] To achieve the above objectives, the present invention provides the following technical solution:

[0015] A hot-swappable expansion system for a non-hot-swappable 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-swappable display interface, and the system also includes a display screen-side expansion circuit, a processor-side expansion circuit and a driver module.

[0016] The display screen extension circuit is located on the display screen driver board and includes a first pin and a flash memory chip, wherein the flash memory chip is connected to the display screen driver board.

[0017] The processor-side expansion circuit is located on the processor side of the host and includes a second pin and a host interface. The host interface is connected to the flash memory chip. The second pin is connected to the first pin.

[0018] The driver module runs in the processor's operating system kernel and includes:

[0019] An interrupt handling unit is used to respond to a level change of the second pin and trigger an interrupt service routine when the display screen is detected to be pulled out.

[0020] The parameter reading unit is used to read the display parameters through the host interface when the insertion of the display is detected;

[0021] The display control unit is used to dynamically initialize the display controller module in the CPU based on the read display parameters.

[0022] Furthermore, the flash memory chip is connected to the display driver board via an I2C bus.

[0023] Furthermore, both the first pin and the second pin are GPIO pins.

[0024] Furthermore, the display parameters include resolution information and timing parameters.

[0025] Furthermore, the flash memory chip stores multiple identical display parameter data, and also stores data accumulation values ​​and cyclic redundancy check values.

[0026] Furthermore, the driver module also includes an event notification unit, which sends a notification to user space via the uevent mechanism or the sysfs file system after detecting a display plugging / unplugging event.

[0027] Furthermore: the non-hot-swappable display interface is an RGB interface or a MIPI-DSI interface.

[0028] A method for detecting a hot-swappable expansion system with a non-hot-swappable display interface includes the following steps:

[0029] S1: Monitors the level status of the pins of the non-hot-pluggable display interface;

[0030] S2: When a change in the level of a pin is detected, the interrupt service routine of the interrupt handling unit is triggered;

[0031] S3: In the interrupt service routine, determine the type of level change. If it is high, determine that the display is inserted; if it is low, determine that the display is removed.

[0032] S4: When it is determined that the display screen is inserted, the display parameters in the flash memory of the display screen are read through the interface and verified. If the verification is successful, the display controller module in the CPU is initialized using the parameters. When it is determined that the display screen is removed, the display parameter resources are released and the display controller module in the CPU is turned off.

[0033] Furthermore, the process of reading and verifying the display parameters in step S4 specifically includes:

[0034] S41: Read two sets of display parameter data from the flash memory and compare whether the two sets of data are consistent;

[0035] S42: Calculate the cumulative sum of the data and the cyclic redundancy check value. If the data is consistent and the check passes, the parameter is confirmed to be valid; if the data is inconsistent or the check fails, the data is read again.

[0036] Furthermore, in step S4, after verifying the read display parameters, the process also includes calling the kernel's drm_helper_hpd_irq_event function to report the display insertion status.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] I. This invention successfully enables hot-swapping functionality for traditional non-hot-swappable display interfaces such as RGB and MIPI-DSI. By adding pins and flash memory chips to the display screen and corresponding pins and host interfaces to the processor, along with a specially designed driver, the display interface, which was originally statically initialized only during system startup, can now support dynamic plugging and unplugging operations during runtime. This fundamentally solves the technical problem of the lack of a native plugging and unplugging detection mechanism for such interfaces.

[0039] Second, this invention achieves dynamic adaptive configuration of display parameters. When a display screen is inserted, the system can automatically read parameters such as resolution and timing stored in flash memory and dynamically initialize the display controller module in the CPU accordingly, without manual intervention or driver recompilation. When connecting displays of different specifications, the system can automatically identify and configure the corresponding display parameters, completely solving the problem of existing solutions relying on preset fixed parameters and being unable to adapt to different displays, significantly improving the system's flexibility and ease of use.

[0040] Third, this invention provides a cross-platform, cross-vendor universal solution. It employs standardized hardware interfaces (GPIO, I2C / SPI) and software design frameworks, independent of any specific vendor's proprietary technology, exhibiting excellent versatility and portability. By using a unified parameter storage format in flash memory, coupled with a robust data verification mechanism, it effectively solves the compatibility issues caused by differences in EDID data formats across different display manufacturers, significantly reducing the costs of system integration and customized adaptation.

[0041] Fourth, the hardware modifications required by this invention are minimal and inexpensive. The entire expansion solution only requires the addition of a few low-cost components to the existing hardware, such as GPIO pins, I2C interfaces, and small-capacity flash memory chips. No modifications to the original display interface protocol are necessary, ensuring complete compatibility with existing systems. This minimal modification approach gives this invention extremely high practical value and widespread application potential.

[0042] V. The system provided by this invention has high reliability. By storing two identical sets of parameter data in flash memory and employing a dual verification mechanism of cumulative summation and cyclic redundancy check, the accuracy and reliability of parameter reading are ensured, effectively avoiding display anomalies caused by data corruption or transmission errors. Simultaneously, the event notification mechanism provided by this invention enables correct response to plug-in / plug-out events from the underlying hardware to the upper-level application, guaranteeing the stable operation of the entire system. Attached Figure Description

[0043] Figure 1 A schematic diagram of the structure of a hot-swappable expansion system for a non-hot-swappable display interface provided by the present invention;

[0044] Figure 2 The flowchart illustrates a method for detecting a hot-swappable expansion system with a non-hot-swappable display interface, as provided by this invention. Detailed Implementation

[0045] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] like Figure 1 As shown, this invention provides a hot-swappable expansion system for a non-hot-swappable display interface. The system mainly includes a display screen, a host computer, a display screen-side expansion circuit, a processor-side expansion circuit, and a driver module. The display screen and the host computer are connected via a non-hot-swappable display interface, such as an RGB interface or a MIPI-DSI interface. These interfaces do not support hot-swapping functionality in traditional designs; this embodiment adds hot-swapping capability through hardware expansion and software integration.

[0048] The display-side expansion circuitry is located on the display driver board and mainly consists of a first pin and a flash memory chip. The voltage level of the first pin changes accordingly when the display is inserted or removed. The flash memory chip stores display parameter information, including key parameters such as 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.

[0049] The processor-side expansion circuitry is located on the processor side of the host computer and includes a second pin and a host interface. The second pin is connected to the first pin on the display side and is used to receive the display's insertion / removal status signal. When the display is inserted, the first pin outputs a high level, and the second pin detects the high-level change; when the display is removed, the first pin outputs a low level, and the second pin detects the low-level change. The host interface is connected to the flash memory chip on the display side and is responsible for reading the display parameters stored in the flash memory.

[0050] The driver module runs within the processor's operating system kernel and is the core software component implementing hot-plug functionality. This module comprises three main functional units. The interrupt handling unit monitors changes in the voltage level of the second pin; upon detecting a change, it triggers the corresponding interrupt service routine. The interrupt service routine determines whether the event is an insertion or removal event based on the voltage level. The parameter reading unit is activated upon detecting a display insertion event and communicates with the flash memory chip on the display side via 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, and timing parameters, ensuring the display functions correctly.

[0051] In one specific embodiment of this example, the flash memory chip and the display driver board are connected via an I2C bus. The I2C bus is a widely used serial communication interface with advantages such as simple connection and few pins required. Through the I2C bus, the processor can easily read data from the flash memory. The flash memory chip, acting as an I2C slave device, has a fixed device address, while the processor, acting as an I2C master device, obtains display parameters by sending read commands and address information.

[0052] In one specific embodiment of this example, both the first and second pins are implemented using GPIO pins. GPIO pins have flexible configuration characteristics, can be set to input or output modes, and support interrupt functionality. On the display side, the first pin is configured as an output mode, outputting a corresponding level according to the display's connection status. On the processor side, the second pin is configured as an input mode and enables interrupt functionality, allowing the interrupt service routine to be triggered immediately upon level changes, achieving rapid response.

[0053] In one specific embodiment of this example, the display screen parameters include resolution information and timing parameters. The resolution information includes the number of horizontal pixels and the number of vertical pixels, such as 1920×1080, 1280×720, etc. The timing parameters include pixel clock frequency, horizontal sync pulse width, horizontal trailing edge, horizontal validity period, horizontal leading edge, vertical sync pulse width, vertical trailing edge, vertical validity period, vertical leading edge, etc. These parameters are crucial for correctly driving the display screen; errors in any of these parameters can lead to display abnormalities.

[0054] In one specific embodiment of this invention, to improve data reliability, the flash memory chip stores two identical copies of the display parameter data. This redundant storage method effectively prevents parameter errors caused by flash memory damage or data bit flipping. Simultaneously, the flash memory also stores a data summation and a cyclic redundancy check (CRC) value. When the processor reads the parameters, it first compares the two sets of data for consistency, then calculates the summation and the CRC value. Only if the data matches and the CRC passes is the parameter considered valid. If data inconsistency is found or the CRC fails, the system attempts to reread the data to ensure the correct parameters are obtained.

[0055] In one specific embodiment of this example, the driver module further includes an event notification unit. This unit, upon detecting a display plug-in / plug event, is responsible for transmitting the event information to the user-space application. The event notification employs standard Linux system mechanisms, including the uevent mechanism and the sysfs file system. Through the uevent mechanism, the kernel can broadcast hot-plug events to user space, and desktop management programs running in user space can listen for these events and take appropriate actions, such as reconfiguring the display layout or adjusting the resolution. Through the sysfs file system, user-space programs can actively query the display's connection status and parameter information.

[0056] In one specific embodiment of this example, 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. The MIPI-DSI interface is a display serial interface standard developed by the Mobile Processor Interface Consortium (MPIC), primarily used in mobile devices and embedded systems. Neither of these interfaces originally supported hot-swapping functionality; however, through the extension scheme of this embodiment, they can acquire hot-swapping capabilities similar to modern interfaces such as HDMI.

[0057] Example 2

[0058] like Figure 2 As shown, the present invention also provides a method for detecting a hot-swappable expansion system with a non-hot-swappable display interface, comprising the following steps.

[0059] First, the system continuously monitors the pin levels of the non-hot-pluggable display interface. This monitoring is achieved through a second pin on the processor side, configured for input mode and with interrupt enabled. Under normal operating conditions, the system is in a low-power standby state and does not require active polling of the pin status.

[0060] When the display is inserted or removed, the voltage level of the first pin changes, and this change is transmitted to the second pin via the connection cable. Upon detecting the voltage change, the second pin immediately generates an interrupt request. Upon receiving the interrupt request, the processor suspends the currently executing program and executes a pre-registered interrupt service routine.

[0061] In the interrupt service routine, the current voltage level of the second pin is first read to determine the type of voltage change. If a high level is detected, it means the display screen has just been inserted; if a low level is detected, it means the display screen has just been removed. This judgment process needs to consider the stability of the voltage level to avoid misjudgments caused by poor contact or electromagnetic interference.

[0062] When a display insertion event is detected, the system initiates a parameter reading process. Through the host interface, the system sends a read command to the flash memory chip on the display screen to obtain the stored display parameters. The reading process follows the I2C communication protocol: first, a start signal is sent; then, the flash memory chip's device address and read command are sent; next, the address of the data to be read is sent; and finally, the data returned by the flash memory is received. 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 output. After initialization, the display screen can display images normally.

[0063] When a display screen removal event is detected, the system executes a cleanup process. First, it stops outputting signals to the display interface to prevent potential hardware damage from outputting signals under no load. Then, it releases previously allocated display parameter memory resources, disables the relevant functional modules of the display controller module in the CPU, and restores the system to standby mode, awaiting the next display screen insertion.

[0064] According to a specific implementation of this embodiment, the system employs multiple safeguards during parameter reading and verification. First, two sets of parameter data are read from the flash memory. These two sets of data were written to different areas of the flash memory during display manufacturing. The system compares whether these two sets of data are completely identical. If they are identical, it indicates that the data is not corrupted. Next, the system calculates the cumulative sum of the read data and compares the calculated result with the cumulative sum stored in the flash memory. Cumulative summation 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. This is a more stringent verification method that can detect error patterns that the CRC cannot detect. Only when the two sets of data are identical, the cumulative sum is correct, and the CRC check passes, does the system consider the parameter valid. If any verification fails, the system will attempt to reread the data, retrying up to three times. If all three attempts fail, the system will report an error and prompt the user to check the hardware connections.

[0065] According to a specific implementation of this embodiment, after the parameter verification passes, the system also needs to call the kernel's display management framework function to report the hot-plug event to the upper-layer 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 user-space display management program, updating the display configuration, and renegotiating the display mode. In this way, the entire system, from the underlying hardware to the upper-layer application, can correctly respond to the display plug-in / plug-out event, achieving complete hot-plug functionality support.

[0066] It should be noted that, in addition to the GPIO pin detection scheme in the above embodiments, this invention can also use capacitive touch detection to replace the GPIO pin detection. The only difference from the above scheme is the detection method. In this scheme, a capacitive sensor is placed near the display interface, and the connection status is determined by the capacitance change caused during insertion and removal. When the display interface is not connected, the capacitive sensor detects the ambient capacitance value; when the display connector approaches or is inserted, the metal contacts and cables change the electric field distribution around the sensor, causing a significant change in capacitance. The system continuously monitors the capacitance value through a dedicated capacitance detection chip. When the detected capacitance value exceeds a preset threshold, it is determined as an insertion event; when the capacitance value drops below the threshold, it is determined as a removal event. This scheme is particularly suitable for space-sensitive micro-devices, such as smartwatches, health monitors, and other wearable devices. Since it does not require additional GPIO pins, this scheme has higher hardware compatibility and can be used in situations where pin resources are extremely limited. The capacitance detection chip communicates with the main processor via an I2C or SPI interface, reporting the detection results to the driver program. Subsequent parameter reading and display initialization processes are the same as in the aforementioned embodiments.

[0067] It should be noted that this invention can also employ voltage / current signal detection to achieve hot-plug sensing. This scheme determines plugging / unplugging events by monitoring voltage or current changes on the power supply line of the display interface. At the moment the display is inserted, a momentary voltage drop or current surge occurs on the power supply line due to the sudden connection of the load; at the moment the display is removed, the load disconnection causes a voltage rebound or current drop. The system connects a precision sampling resistor in series on the power supply line and acquires voltage or current signals in real time through a high-speed analog-to-digital converter. When a signal change is detected exceeding a set threshold, the corresponding plugging / unplugging event handling program is triggered. This scheme is particularly suitable for high-reliability equipment in industrial control fields, such as PLC control panels and industrial human-machine interfaces. To improve detection accuracy, 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, notifying the main processor via an interrupt, avoiding the power consumption problems caused by continuous polling.

[0068] It should be noted that, at the software level, this 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, triggering once per second, to check the display's connection status during timer interrupts. Simultaneously, the system retains a GPIO interrupt detection mechanism for rapid response to plug / removal 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 the plug / removal status. This hybrid mechanism effectively avoids interrupt storms caused by poor contact 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; reducing reliance on interrupt resources improves overall system stability. The polling frequency can be dynamically adjusted according to the application scenario, increasing the frequency in situations with high real-time requirements and decreasing the frequency in standby mode to save power.

[0069] It should be noted that this invention can also employ an event-driven asynchronous reporting model. In this model, the underlying plug-in / plug-out detection module encapsulates detected events into standard asynchronous messages and publishes them through the system's message bus (such as D-Bus in Linux or Binder in Android). Upper-layer display management services, desktop environments, and applications can subscribe to these messages and process them according to their own needs. This design completely decouples the hardware detection layer from the business logic layer, resulting in better modularity and scalability. For example, upon receiving an insertion event, the display management service can automatically adjust the desktop resolution and layout; the media playback application can automatically switch output modes based on the display's connection status; and the system monitoring service can record plug-in / plug-out event logs for fault diagnosis. The message format uses a standard key-value pair structure, containing information such as 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, fully utilizing the system's infrastructure, reducing development complexity, and improving system maintainability.

[0070] It should be noted that this invention can also use the SPI bus to read display parameters in terms of bus protocol. Compared with the I2C bus used in the previous embodiments, the SPI bus has a higher data transmission rate, reaching tens of megabits per second or even higher. However, using the SPI bus also brings some hardware design challenges. In addition to needing to add chip select signal lines, the SPI bus has higher requirements for signal integrity, requiring 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 program 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 complex than the implementation of the I2C bus, but still within an acceptable range.

[0071] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within 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, the display screen and the host being connected, wherein the display screen is provided with a non-hot-swappable display interface, characterized in that: It also includes display-side expansion circuitry, processor-side expansion circuitry, and driver module; The display screen extension circuit is located on the display screen driver board and includes a first pin and a flash memory chip, wherein the flash memory chip is connected to the display screen driver board. The processor-side expansion circuit is located 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 processor's operating system kernel and includes: An interrupt handling unit is used to respond to a level change of the second pin and trigger an interrupt service routine when the display screen is detected to be pulled out. The parameter reading unit is used to read display parameters through the host interface when the insertion of the display screen is detected. The display control unit is used to dynamically initialize the display controller module in the CPU based on the read display parameters. The display screen parameters include resolution information and timing parameters; The flash memory chip stores multiple identical display parameter data, and also stores data accumulation values ​​and cyclic redundancy check values. The driver module also includes an event notification unit, which sends a notification to user space via the uevent mechanism or the sysfs file system after detecting a display plugging / unplugging event. The non-hot-swappable display interface is either an RGB interface or a MIPI-DSI interface.

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

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

4. A method for detecting a hot-swappable expansion system with a non-hot-swappable display interface, applied to the hot-swappable expansion system with a non-hot-swappable display interface as described in any one of claims 1-3, characterized in that, Includes the following steps: S1: Monitors the level status of the pins of the non-hot-pluggable display interface; S2: When a change in the level of a pin is detected, the interrupt service routine of the interrupt handling unit is triggered; S3: In the interrupt service routine, determine the type of level change. If it is high, determine that the display is inserted; if it is low, determine that the display is removed. S4: When it is determined that the display screen is inserted, the display parameters in the flash memory of the display screen are read through the interface and verified. If the verification is successful, the display controller module in the CPU is initialized using the parameters. When it is determined that the display screen is removed, the display parameter resources are released and the display controller module in the CPU is turned off.

5. The detection method for a hot-swappable expansion system of a non-hot-swappable display interface according to claim 4, characterized in that: The process of reading and verifying the display parameters in step S4 specifically includes: S41: Read two sets of display parameter data from the flash memory and compare whether the two sets 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, the parameter is confirmed to be valid; if the data is inconsistent or the check fails, the data is read again.

6. The detection method for a hot-swappable expansion system of a non-hot-swappable display interface according to claim 4, characterized in that: In step S4, after verifying the read display parameters, the process also includes calling the kernel's drm_helper_hpd_irq_event function to report the display insertion status.

Images