Some panels are connected through extension boards an provide an easy way for the main board to detect when they are present (like checking for a working I2C communication with a device and making sure a specific reg in this device has a consistent value). When this is the case, we might want to support dynamic panel detection and only expose the display (and its display modes) when the panel is detected, similar to the monitor detection we use for regular connectors (HDMI, DVI, ...). This solves a problem we have on the Rpi when the panel is not connected to the board but described in the DT. This prevents the whole display pipeline from being exposed because one of the element (the panel) is missing. This was posted as an RFC because I'm not sure dynamically detecting panels or supporting panel hotplug is actually something we want to do. Thierry, and DRM folks in general, feel free to give your opinion on this approach, and/or propose others solution to solve the "DSI panel not connected" problem we have on RPi. Oh, and before someone suggests it, IIRC, Eric wanted to avoid relying on DT overlays to do that, I don't remember why though. Regards, Boris Boris Brezillon (3): drm/panel: Support panel detection drm/bridge: panel: Make use of the panel detection infrastructure drm/panel: rpi-touchscreen: Implement ->detect() drivers/gpu/drm/bridge/panel.c | 13 +++++ .../gpu/drm/panel/panel-raspberrypi-touchscreen.c | 62 ++++++++++++++++++---- include/drm/drm_panel.h | 12 +++++ 3 files changed, 78 insertions(+), 9 deletions(-) -- 2.14.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
