drm/amd/display: explicitly set is_dsc_supported to false before use

superm1 · alexdeucher · commit 63ad5371cd1e · 2022-01-11T15:44:25.000-05:00
When UBSAN is enabled a case is shown on unplugging the display that this variable hasn't been initialized by `update_dsc_caps`, presumably when the display was unplugged it wasn't copied from the DPCD. Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1956497 Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Acked-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6097,6 +6097,7 @@ static void update_dsc_caps(struct amdgpu_dm_connector *aconnector,
 							struct dsc_dec_dpcd_caps *dsc_caps)
 {
 	stream->timing.flags.DSC = 0;
+	dsc_caps->is_dsc_supported = false;
 
 	if (aconnector->dc_link && (sink->sink_signal == SIGNAL_TYPE_DISPLAY_PORT ||
 		sink->sink_signal == SIGNAL_TYPE_EDP)) {

Original file line number	Diff line number	Diff line change
`@@ -6097,6 +6097,7 @@ static void update_dsc_caps(struct amdgpu_dm_connector *aconnector,`
`6097`	`6097`	`struct dsc_dec_dpcd_caps *dsc_caps)`
`6098`	`6098`	`{`
`6099`	`6099`	`stream->timing.flags.DSC = 0;`
	`6100`	`+ dsc_caps->is_dsc_supported = false;`
`6100`	`6101`
`6101`	`6102`	`if (aconnector->dc_link && (sink->sink_signal == SIGNAL_TYPE_DISPLAY_PORT \|\|`
`6102`	`6103`	`sink->sink_signal == SIGNAL_TYPE_EDP)) {`