[PATCH 10/25] drm/amd/display: dereference variable before checking for zero

Wayne Lin Wayne.Lin at amd.com
Wed Dec 13 06:12:12 UTC 2023


From: Josip Pavic <josip.pavic at amd.com>

[Why]
Driver incorrectly checks if pointer variable OutBpp is null instead of
if the value being pointed to is zero.

[How]
Dereference OutBpp before checking for a value of zero.

Reviewed-by: Chaitanya Dhere <chaitanya.dhere at amd.com>
Acked-by: Wayne Lin <wayne.lin at amd.com>
Signed-off-by: Josip Pavic <josip.pavic at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c b/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c
index 180f8a98a361..b95bf27f2fe2 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c
@@ -5420,7 +5420,7 @@ static void CalculateOutputLink(
 					*OutBpp = TruncToValidBPP((1 - Downspreading / 100) * 13500, OutputLinkDPLanes, HTotal, HActive, PixelClockBackEnd, ForcedOutputLinkBPP, LinkDSCEnable, Output,
 												OutputFormat, DSCInputBitPerComponent, NumberOfDSCSlices, (dml_uint_t)AudioSampleRate, AudioSampleLayout, ODMModeNoDSC, ODMModeDSC, RequiredSlots);
 
-					if (OutBpp == 0 && PHYCLKD32PerState < 20000 / 32 && DSCEnable == dml_dsc_enable_if_necessary && ForcedOutputLinkBPP == 0) {
+					if (*OutBpp == 0 && PHYCLKD32PerState < 20000 / 32 && DSCEnable == dml_dsc_enable_if_necessary && ForcedOutputLinkBPP == 0) {
 						*RequiresDSC = true;
 						LinkDSCEnable = true;
 						*OutBpp = TruncToValidBPP((1 - Downspreading / 100) * 13500, OutputLinkDPLanes, HTotal, HActive, PixelClockBackEnd, ForcedOutputLinkBPP, LinkDSCEnable, Output,
-- 
2.37.3



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