[PATCH 15/26] drm/amd/display: Increase EDID read retries

[Alex Hung <alex.hung@amd.com>]

From: "Mario Limonciello (AMD)" <superm1@kernel.org>

[WHY]
When monitor is still booting EDID read can fail while DPCD read
is successful.  In this case no EDID data will be returned, and this
could happen for a while.

[HOW]
Increase number of attempts to read EDID in dm_helpers_read_local_edid()
to 25.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4672

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Alex Hung <alex.hung@amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index 582a1c04f035..e5e993d3ef74 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -1006,8 +1006,8 @@ enum dc_edid_status dm_helpers_read_local_edid(
 	struct amdgpu_dm_connector *aconnector = link->priv;
 	struct drm_connector *connector = &aconnector->base;
 	struct i2c_adapter *ddc;
-	int retry = 3;
-	enum dc_edid_status edid_status;
+	int retry = 25;
+	enum dc_edid_status edid_status = EDID_NO_RESPONSE;
 	const struct drm_edid *drm_edid;
 	const struct edid *edid;
 
@@ -1037,7 +1037,7 @@ enum dc_edid_status dm_helpers_read_local_edid(
 		}
 
 		if (!drm_edid)
-			return EDID_NO_RESPONSE;
+			continue;
 
 		edid = drm_edid_raw(drm_edid); // FIXME: Get rid of drm_edid_raw()
 		if (!edid ||
@@ -1055,7 +1055,7 @@ enum dc_edid_status dm_helpers_read_local_edid(
 						&sink->dc_edid,
 						&sink->edid_caps);
 
-	} while (edid_status == EDID_BAD_CHECKSUM && --retry > 0);
+	} while ((edid_status == EDID_BAD_CHECKSUM || edid_status == EDID_NO_RESPONSE) && --retry > 0);
 
 	if (edid_status != EDID_OK)
 		DRM_ERROR("EDID err: %d, on connector: %s",
-- 
2.43.0