[PATCH 1/1][SRU][Jammy] drm/amd/display: explicitly set is_dsc_supported to false before use

[You-Sheng Yang]

From: Mario Limonciello <mario.limonciello at amd.com>

BugLink: https://bugs.launchpad.net/bugs/1956497

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 at amd.com>
Acked-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
(cherry picked from commit 63ad5371cd1e379519395c49a4b6a652c36c98e5)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 3b09b21f1ac2..e44eb17e2243 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5811,6 +5811,7 @@ 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) {
 		dc_dsc_parse_dsc_dpcd(aconnector->dc_link->ctx->dc,
-- 
2.33.1