kernel/drivers/gpu/drm/amd/display/dc/bios, branch linux-rolling-stable

drm/amd/display: Initialize DAC in DCE link encoder using VBIOS

2026-02-26T23:01:38Z

[ Upstream commit e2a024345bce78a8e1ed7d9e84c859b05979e41e ] The VBIOS DAC1EncoderControl() function can initialize the DAC, by writing board-specific values to certain registers. Call this at link encoder hardware initialization time similarly to how the equivalent UNIPHYTransmitterControl initialization is done. This fixes DAC output on the Radeon HD 7790. Also remove the ENCODER_CONTROL_SETUP enum from the dac_encoder_control_prepare_params function which is actually not a supported operation for DAC encoders. Fixes: 0fbe321a93ce ("drm/amd/display: Implement DCE analog link encoders (v2)") Signed-off-by: Timur Kristóf Tested-by: Mauro Rossi Suggested-by: Alex Deucher Reviewed-by: Alex Hung Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Add missing encoder setup to DACnEncoderControl

2026-01-05T22:33:28Z

Apparently the DAC encoder needs to be set up before use. The BIOS parser in DC did not support this so I assumed it was not necessary, but the DAC doesn't work without it on some GPUs. Fixes: 69b29b894660 ("drm/amd/display: Hook up DAC to bios_parser_encoder_control") Reviewed-by: Alex Deucher Signed-off-by: Timur Kristóf Signed-off-by: Alex Deucher (cherry picked from commit bb5dfe2f5630ce344c654c705d28b4e20cb9d334)

drm/amd/display: Correct color depth for SelectCRTC_Source

2026-01-05T22:31:24Z

Pass the correct enum values as expected by the VBIOS. Previously the actual bit depth integer value was passed, which was a mistake. Fixes: 7fb4f254c8eb ("drm/amd/display: Add SelectCRTC_Source to BIOS parser") Reviewed-by: Alex Deucher Signed-off-by: Timur Kristóf Signed-off-by: Alex Deucher (cherry picked from commit cdf6e4c0cdab129ffc4e41a8ac53a0738f805072)

drm/amd/display: Check ATOM_DEVICE_CRT2_SUPPORT in dc_load_detection

2025-11-26T16:35:22Z

[WHY & HOW] Fix the typo of the else-if condition from ATOM_DEVICE_CRT1_SUPPORT to ATOM_DEVICE_CRT2_SUPPORT. Reviewed-by: Harry Wentland Signed-off-by: Ivan Lipski Signed-off-by: Alex Hung Tested-by: Dan Wheeler Signed-off-by: Alex Deucher

drm/amd/display: Fix logical vs bitwise bug in get_embedded_panel_info_v2_1()

2025-11-26T16:29:08Z

The .H_SYNC_POLARITY and .V_SYNC_POLARITY variables are 1 bit bitfields of a u32. The ATOM_HSYNC_POLARITY define is 0x2 and the ATOM_VSYNC_POLARITY is 0x4. When we do a bitwise negate of 0, 2, or 4 then the last bit is always 1 so this code always sets .H_SYNC_POLARITY and .V_SYNC_POLARITY to true. This code is instead intended to check if the ATOM_HSYNC_POLARITY or ATOM_VSYNC_POLARITY flags are set and reverse the result. In other words, it's supposed to be a logical negate instead of a bitwise negate. Fixes: ae79c310b1a6 ("drm/amd/display: Add DCE12 bios parser support") Signed-off-by: Dan Carpenter Reviewed-by: Alex Hung Signed-off-by: Alex Deucher

drm/amd/display: Add DAC_LoadDetection to BIOS parser (v2)

2025-10-28T14:09:55Z

DAC_LoadDetection can be used to determine whether something is connected to an analog connector by determining if there is an analog load. This causes visible flickering on displays, so we only resort to using this when the connected display doesn't have an EDID. For reference, see the legacy display code: amdgpu_atombios_encoder_dac_load_detect v2: Only clear corresponding bit from BIOS_SCRATCH_0. Signed-off-by: Timur Kristóf Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher

drm/amd/display: Make get_support_mask_for_device_id reusable

2025-10-28T14:09:46Z

This will be reused by DAC load detection. Signed-off-by: Timur Kristóf Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher

drm/amd/display: Get maximum pixel clock from VBIOS

2025-10-28T14:08:36Z

We will use this for validating the pixel clock when an analog monitor is connected to VGA or DVI-I connectors. For reference, see the legacy display code: amdgpu_connector_vga_mode_valid Signed-off-by: Timur Kristóf Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher

drm/amd/display: Add SelectCRTC_Source to BIOS parser

2025-10-28T14:08:24Z

The SelectCRTC_Source command will be used to change which CRTC should be connected to which encoder. For reference, see the legacy display code: amdgpu_atombios_encoder_set_crtc_source Signed-off-by: Timur Kristóf Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher

drm/amd/display: Hook up DAC to bios_parser_encoder_control

2025-10-28T14:08:20Z

Enable the codebase to use encoder_control() when the encoder engine is one of the DACs. The BIOS parser already supports calling the DAC1EncoderControl function from the VBIOS, but it was not exposed anywhere. Signed-off-by: Timur Kristóf Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher