From 106b4a2a78b2a2f14885604891957b84bba502db Mon Sep 17 00:00:00 2001 From: Adrian Betschart Date: Fri, 11 Sep 2026 17:13:14 +0200 Subject: drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validation amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and uses the first encoding that validates. YCbCr 4:4:4 is listed before RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the "color format" property is left at AUTO, even though RGB fits the same link. That contradicts the documented AUTO behaviour for HDMI in enum drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when the bandwidth is not available or the mode is 4:2:0-only), which the amdgpu implementation of the property also describes. It also leaves the "Broadcast RGB" property without effect on such sinks, since the quantization range it selects only applies to RGB output. Try RGB first. The mask still holds every encoding the sink supports, so a mode that cannot carry RGB falls back exactly as before. For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI sink that advertised it. Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation") Suggested-by: Adolfo Rodrigues Assisted-by: Claude Code:claude-fable-5-1 Signed-off-by: Adrian Betschart Reviewed-by: Fangzhi Zuo Tested-by: Adolfo Rodrigues Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7) --- Documentation/gpu/amdgpu/driver-misc.rst | 156 +++++++++++++++++++++++++++++++ 1 file changed, 156 insertions(+) create mode 100644 Documentation/gpu/amdgpu/driver-misc.rst (limited to 'Documentation/gpu/amdgpu/driver-misc.rst') diff --git a/Documentation/gpu/amdgpu/driver-misc.rst b/Documentation/gpu/amdgpu/driver-misc.rst new file mode 100644 index 000000000..e1a964c3a --- /dev/null +++ b/Documentation/gpu/amdgpu/driver-misc.rst @@ -0,0 +1,156 @@ +================================ + Misc AMDGPU driver information +================================ + +GPU Product Information +======================= + +Information about the GPU can be obtained on certain cards +via sysfs + +product_name +------------ + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c + :doc: product_name + +product_number +-------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c + :doc: product_number + +serial_number +------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c + :doc: serial_number + +fru_id +------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c + :doc: fru_id + +manufacturer +------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c + :doc: manufacturer + +unique_id +--------- + +.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c + :doc: unique_id + +board_info +---------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c + :doc: board_info + +GPU Memory Usage Information +============================ + +Various memory accounting can be accessed via sysfs + +mem_info_vram_total +------------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c + :doc: mem_info_vram_total + +mem_info_vram_used +------------------ + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c + :doc: mem_info_vram_used + +mem_info_vis_vram_total +----------------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c + :doc: mem_info_vis_vram_total + +mem_info_vis_vram_used +---------------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c + :doc: mem_info_vis_vram_used + +mem_info_gtt_total +------------------ + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c + :doc: mem_info_gtt_total + +mem_info_gtt_used +----------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c + :doc: mem_info_gtt_used + +PCIe Accounting Information +=========================== + +pcie_bw +------- + +.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c + :doc: pcie_bw + +pcie_replay_count +----------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c + :doc: pcie_replay_count + +GPU SmartShift Information +========================== + +GPU SmartShift information via sysfs + +smartshift_apu_power +-------------------- + +.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c + :doc: smartshift_apu_power + +smartshift_dgpu_power +--------------------- + +.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c + :doc: smartshift_dgpu_power + +smartshift_bias +--------------- + +.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c + :doc: smartshift_bias + +UMA Carveout +============ + +Some versions of Atom ROM expose available options for the VRAM carveout sizes, +and allow changes to the carveout size via the ATCS function code 0xA on supported +BIOS implementations. + +For those platforms, users can use the following files under uma/ to set the +carveout size, in a way similar to what Windows users can do in the "Tuning" +tab in AMD Adrenalin. + +Note that for BIOS implementations that don't support this, these files will not +be created at all. + +uma/carveout_options +-------------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c + :doc: uma/carveout_options + +uma/carveout +-------------------- + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c + :doc: uma/carveout -- cgit v1.3.1