[PATCH AUTOSEL 5.14 144/252] drm/msm/dp: return correct edid checksum after corrupted edid checksum read

Sasha Levin
2021-09-09T11:55:01Z

From: Kuogee Hsieh <khsieh@codeaurora.org>

[ Upstream commit 7948fe12d47a946fb8025a0534c900e3dd4b5839 ]

Response with correct edid checksum saved at connector after corrupted edid
checksum read. This fixes Link Layer CTS cases 4.2.2.3, 4.2.2.6.

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/1628196295-7382-6-git-send-email-khsieh@codeaurora.org
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/dp/dp_panel.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 440b32753430..2181b60e1d1d 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -271,7 +271,7 @@ static u8 dp_panel_get_edid_checksum(struct edid *edid)
{
struct edid *last_block;
u8 *raw_edid;
- bool is_edid_corrupt;
+ bool is_edid_corrupt = false;

if (!edid) {
DRM_ERROR("invalid edid input\n");
@@ -303,7 +303,12 @@ void dp_panel_handle_sink_request(struct dp_panel *dp_panel)
panel = container_of(dp_panel, struct dp_panel_private, dp_panel);

if (panel->link->sink_request & DP_TEST_LINK_EDID_READ) {
- u8 checksum = dp_panel_get_edid_checksum(dp_panel->edid);
+ u8 checksum;
+
+ if (dp_panel->edid)
+ checksum = dp_panel_get_edid_checksum(dp_panel->edid);
+ else
+ checksum = dp_panel->connector->real_edid_checksum;

dp_link_send_edid_checksum(panel->link, checksum);
dp_link_send_test_response(panel->link);
--
2.30.2