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mirror of synced 2025-03-06 20:59:54 +01:00

drm: Fix DSC BPP increment decoding

Starting with DPCD version 2.0 bits 6:3 of the DP_DSC_BITS_PER_PIXEL_INC
DPCD register contains the NativeYCbCr422_MAX_bpp_DELTA field, which can
be non-zero as opposed to earlier DPCD versions, hence decoding the
bit_per_pixel increment value at bits 2:0 in the same register requires
applying a mask, do so.

Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Fixes: 0c2287c965 ("drm/display/dp: Add helper function to get DSC bpp precision")
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250212161851.4007005-1-imre.deak@intel.com
This commit is contained in:
Imre Deak 2025-02-12 18:18:51 +02:00
parent 9ab127a180
commit e00a2e5d48
2 changed files with 2 additions and 1 deletions

View file

@ -2544,7 +2544,7 @@ u8 drm_dp_dsc_sink_bpp_incr(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
{
u8 bpp_increment_dpcd = dsc_dpcd[DP_DSC_BITS_PER_PIXEL_INC - DP_DSC_SUPPORT];
switch (bpp_increment_dpcd) {
switch (bpp_increment_dpcd & DP_DSC_BITS_PER_PIXEL_MASK) {
case DP_DSC_BITS_PER_PIXEL_1_16:
return 16;
case DP_DSC_BITS_PER_PIXEL_1_8:

View file

@ -359,6 +359,7 @@
# define DP_DSC_BITS_PER_PIXEL_1_4 0x2
# define DP_DSC_BITS_PER_PIXEL_1_2 0x3
# define DP_DSC_BITS_PER_PIXEL_1_1 0x4
# define DP_DSC_BITS_PER_PIXEL_MASK 0x7
#define DP_PSR_SUPPORT 0x070 /* XXX 1.2? */
# define DP_PSR_IS_SUPPORTED 1