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From:   Kuogee Hsieh <khsieh@codeaurora.org>
To:     dri-devel@lists.freedesktop.org, robdclark@gmail.com,
        sean@poorly.run, swboyd@chromium.org
Cc:     Kuogee Hsieh <khsieh@codeaurora.org>, abhinavk@codeaurora.org,
        aravindh@codeaurora.org, airlied@linux.ie, daniel@ffwll.ch,
        bjorn.andersson@linaro.org, linux-arm-msm@vger.kernel.org,
        freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 5/6] drm/msm/dp: return correct edid checksum after corrupted edid checksum read
Date:   Thu,  5 Aug 2021 13:44:54 -0700
Message-Id: <1628196295-7382-6-git-send-email-khsieh@codeaurora.org>
In-Reply-To: <1628196295-7382-1-git-send-email-khsieh@codeaurora.org>
References: <1628196295-7382-1-git-send-email-khsieh@codeaurora.org>
Precedence: bulk

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>
---
 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 88196f7..0fdb551 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);
-- 
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