Display Hotplug Buffering to Prevent Flicker During Rebalancing
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Solution Overview
Problem
When a new display device is hotplugged to a computer system, the graphics subsystem may temporarily lack resources to drive existing displays, leading to flashing or flickering due to insufficient resource rebalancing.
Innovation Solution
The techniques provide the graphics subsystem with time to adjust resource balance between displays while minimizing disruption to currently attached displays by optimizing resource rebalancing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the graphics subsystem immediately re-assigns resources from existing displays to the newly attached display, then the new display can be driven, but the existing displays may temporarily lack resources causing flickering
Solution Approach 1:
The system performs preliminary actions by detecting the hotplug event and initiating resource rebalancing before the new display fully takes resources. The graphics subsystem proactively identifies the need for rebalancing and begins the transition process, preventing the temporary resource shortage that causes flickering on existing displays.
Solution Approach 2:
The resource allocation is made dynamic rather than static. The graphics subsystem continuously monitors display connections and dynamically adjusts resource distribution between displays based on current system state. This dynamic rebalancing allows smooth transitions without disrupting existing display operations.
2Adaptability or versatility
If the graphics subsystem takes resources from existing displays to drive the new display, then the new display becomes operational, but visual disruption occurs on existing displays
Solution Approach 1:
The system introduces an intermediary resource pool or buffer mechanism that facilitates smooth resource transitions. Instead of directly taking resources from existing displays, the graphics subsystem uses intermediate resources or staged allocation to bridge the transition, preventing the harmful flickering effect while maintaining adaptability to new display connections.
Solution Approach 2:
The graphics subsystem prepares compensatory measures in advance by maintaining resource reserves or pre-configuring fallback allocations. When a new display is hotplugged, these pre-prepared resources cushion the transition, ensuring existing displays maintain sufficient resources to avoid flickering while the new display is brought online.
Data Source
AI summary
One embodiment provides a graphics processor device that includes circuitry configured to detect a connection of a second display device to a display subsystem of the graphics processor while a first display device of the graphics subsystem is active, write pre-determined pixel data to a reserved portion of memory associated with the display subsystem, configure timings for the second display device while resources allocated to the first display device remain available to the first display device, display the pre-determined pixel data from the reserved portion of the memory on the second display device during reallocation of the resources of the display subsystem to enable output the framebuffer data to the second display device, and transition the second display device from the display of the pixel data in the reserved portion of the memory to the display of the framebuffer data after resources of the display subsystem are reallocated.