[PATCH 1/2] drm/dsc: fix drm_edp_dsc_sink_output_bpp() DPCD high byte usage

[Jani Nikula]

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 at intel.com>
Cc: Manasi Navare <navaremanasi at google.com>
Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
Cc: <stable at vger.kernel.org> # v5.0+
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 include/drm/display/drm_dp.h        | 1 -
 include/drm/display/drm_dp_helper.h | 5 ++---
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
index 358db4a9f167..89d5a700b04d 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 533d3ee7fe05..86f24a759268 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
-- 
2.39.2