This is a note to let you know that I've just added the patch titled
drm/dsc: fix drm_edp_dsc_sink_output_bpp() DPCD high byte usage
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-dsc-fix-drm_edp_dsc_sink_output_bpp-dpcd-high-by.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 46276d09550c0d750dcb46c363c490441296677a
Author: Jani Nikula <jani.nikula@xxxxxxxxx>
Date: Thu Apr 6 16:46:14 2023 +0300
drm/dsc: fix drm_edp_dsc_sink_output_bpp() DPCD high byte usage
[ Upstream commit 13525645e2246ebc8a21bd656248d86022a6ee8f ]
The operator precedence between << and & is wrong, leading to the high
byte being completely ignored. For example, with the 6.4 format, 32
becomes 0 and 24 becomes 8. Fix it, and remove the slightly confusing
and unnecessary DP_DSC_MAX_BITS_PER_PIXEL_HI_SHIFT macro while at it.
Fixes: 0575650077ea ("drm/dp: DRM DP helper/macros to get DP sink DSC parameters")
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
Cc: Manasi Navare <navaremanasi@xxxxxxxxxx>
Cc: Anusha Srivatsa <anusha.srivatsa@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v5.0+
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20230406134615.1422509-1-jani.nikula@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
index 9bc22a02874d9..50428ba92ce8b 100644
--- a/include/drm/display/drm_dp.h
+++ b/include/drm/display/drm_dp.h
@@ -286,7 +286,6 @@
#define DP_DSC_MAX_BITS_PER_PIXEL_HI 0x068 /* eDP 1.4 */
# define DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK (0x3 << 0)
-# define DP_DSC_MAX_BITS_PER_PIXEL_HI_SHIFT 8
# define DP_DSC_MAX_BPP_DELTA_VERSION_MASK 0x06
# define DP_DSC_MAX_BPP_DELTA_AVAILABILITY 0x08
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
index ab55453f2d2cd..ade9df59e156a 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -181,9 +181,8 @@ static inline u16
drm_edp_dsc_sink_output_bpp(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
{
return dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_LOW - DP_DSC_SUPPORT] |
- (dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] &
- DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK <<
- DP_DSC_MAX_BITS_PER_PIXEL_HI_SHIFT);
+ ((dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] &
+ DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK) << 8);
}
static inline u32
