[PATCH AUTOSEL 6.6 19/40] drm/msm/dp: skip validity check for DP CTS EDID checksum

[Sasha Levin]

From: Jani Nikula <jani.nikula at intel.com>

[ Upstream commit a251c9d8e30833b260101edb9383b176ee2b7cb1 ]

The DP CTS test for EDID last block checksum expects the checksum for
the last block, invalid or not. Skip the validity check.

For the most part (*), the EDIDs returned by drm_get_edid() will be
valid anyway, and there's the CTS workaround to get the checksum for
completely invalid EDIDs. See commit 7948fe12d47a ("drm/msm/dp: return
correct edid checksum after corrupted edid checksum read").

This lets us remove one user of drm_edid_block_valid() with hopes the
function can be removed altogether in the future.

(*) drm_get_edid() ignores checksum errors on CTA extensions.

Cc: Abhinav Kumar <quic_abhinavk at quicinc.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
Cc: Kuogee Hsieh <khsieh at codeaurora.org>
Cc: Marijn Suijten <marijn.suijten at somainline.org>
Cc: Rob Clark <robdclark at gmail.com>
Cc: Sean Paul <sean at poorly.run>
Cc: Stephen Boyd <swboyd at chromium.org>
Cc: linux-arm-msm at vger.kernel.org
Cc: freedreno at lists.freedesktop.org
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Reviewed-by: Stephen Boyd <swboyd at chromium.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
Reviewed-by: Kuogee Hsieh <quic_khsieh at quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/555361/
Link: https://lore.kernel.org/r/20230901142034.580802-1-jani.nikula@intel.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/msm/dp/dp_panel.c | 21 ++-------------------
 1 file changed, 2 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
index 42d52510ffd4a..86a8e06c7a60f 100644
--- a/drivers/gpu/drm/msm/dp/dp_panel.c
+++ b/drivers/gpu/drm/msm/dp/dp_panel.c
@@ -289,26 +289,9 @@ int dp_panel_get_modes(struct dp_panel *dp_panel,
 
 static u8 dp_panel_get_edid_checksum(struct edid *edid)
 {
-	struct edid *last_block;
-	u8 *raw_edid;
-	bool is_edid_corrupt = false;
+	edid += edid->extensions;
 
-	if (!edid) {
-		DRM_ERROR("invalid edid input\n");
-		return 0;
-	}
-
-	raw_edid = (u8 *)edid;
-	raw_edid += (edid->extensions * EDID_LENGTH);
-	last_block = (struct edid *)raw_edid;
-
-	/* block type extension */
-	drm_edid_block_valid(raw_edid, 1, false, &is_edid_corrupt);
-	if (!is_edid_corrupt)
-		return last_block->checksum;
-
-	DRM_ERROR("Invalid block, no checksum\n");
-	return 0;
+	return edid->checksum;
 }
 
 void dp_panel_handle_sink_request(struct dp_panel *dp_panel)
-- 
2.42.0