drm/radeon: retry dcpd fetch
Retry the dpcd fetch several times. Some eDP panels
fail several times before the fetch is successful.
bug:
https://bugs.freedesktop.org/show_bug.cgi?id=73530
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 3e3290c..b435c85 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -421,19 +421,21 @@
{
struct radeon_connector_atom_dig *dig_connector = radeon_connector->con_priv;
u8 msg[DP_DPCD_SIZE];
- int ret;
+ int ret, i;
- ret = drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_DPCD_REV, msg,
- DP_DPCD_SIZE);
- if (ret > 0) {
- memcpy(dig_connector->dpcd, msg, DP_DPCD_SIZE);
+ for (i = 0; i < 7; i++) {
+ ret = drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_DPCD_REV, msg,
+ DP_DPCD_SIZE);
+ if (ret == DP_DPCD_SIZE) {
+ memcpy(dig_connector->dpcd, msg, DP_DPCD_SIZE);
- DRM_DEBUG_KMS("DPCD: %*ph\n", (int)sizeof(dig_connector->dpcd),
- dig_connector->dpcd);
+ DRM_DEBUG_KMS("DPCD: %*ph\n", (int)sizeof(dig_connector->dpcd),
+ dig_connector->dpcd);
- radeon_dp_probe_oui(radeon_connector);
+ radeon_dp_probe_oui(radeon_connector);
- return true;
+ return true;
+ }
}
dig_connector->dpcd[0] = 0;
return false;