Hi Mykhailo, Nicolas has took over this series, check this: https://patchwork.kernel.org/project/linux-rockchip/cover/[email protected]/
Best regards, Shengyu 在 2026/2/14 18:56, Mykhailo Kalashnikov 写道:
Hi Shengyu, I've been testing your pixel_encoding patch series (v2) on kernel 6.18.5 with an AMD RX 9070 XT (gfx1201/Navi 48) and found two bugs where PIXEL_ENCODING_YCBCR422 handling is missing. Both get_connector_state_pixel_encoding() and dc_pixel_encoding_to_drm_prop() handle RGB, YCBCR444, and YCBCR420 but are missing the YCBCR422 case. This causes YCbCr 4:2:2 to never be applied — the switch falls through to default, get_connector_state_pixel_encoding() returns false, and auto-select picks RGB instead. Fix 1: get_connector_state_pixel_encoding() missing YCBCR422 ------------------------------------------------------------- case PIXEL_ENCODING_YCBCR444: ret = (info->color_formats & DRM_COLOR_FORMAT_YCBCR444); break; + case PIXEL_ENCODING_YCBCR422: + ret = (info->color_formats & DRM_COLOR_FORMAT_YCBCR422); + break; case PIXEL_ENCODING_YCBCR420: ret = drm_mode_is_420(info, mode_in); break; Fix 2: dc_pixel_encoding_to_drm_prop() missing YCBCR422 -------------------------------------------------------- case PIXEL_ENCODING_YCBCR444: propval = DRM_COLOR_FORMAT_YCBCR444; break; + case PIXEL_ENCODING_YCBCR422: + propval = DRM_COLOR_FORMAT_YCBCR422; + break; case PIXEL_ENCODING_YCBCR420: propval = DRM_COLOR_FORMAT_YCBCR420; break; Both are in drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c. Tested with amdgpu.pixel_encoding=DP-2:ycbcr422 on the following setup: GPU: AMD RX 9070 XT (gfx1201 / Navi 48) Kernel: 6.18.5 KVM: TESmart HKD402-M24 (DP 1.4 in, HDMI 2.1 out) Monitor: Dell AW3225QF (HDMI 2.1) Link: GPU DP 1.4 -> KVM -> HDMI 2.1 -> Monitor Without these fixes, the module parameter is accepted but ignored — display stays in RGB. With both fixes, YCbCr 4:2:2 is correctly applied and confirmed via modetest (pixel encoding property value: 4). Thanks for the patch series — it fills an important gap for users with DP-to-HDMI KVM setups who need non-RGB pixel encoding. Regards, Mykhailo Kalashnikov
OpenPGP_0xE3520CC91929C8E7.asc
Description: OpenPGP public key
OpenPGP_signature.asc
Description: OpenPGP digital signature
