drm/radeon/kms: retry auxch on 0x20 timeout value.
ATOM appears to return 0x20 which seems to mean some sort of timeout.
retry the transaction up to 10 times before failing, this
makes DP->VGA convertor we bought work at least a bit more predictably.
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 7106011..b32eeea 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -332,11 +332,13 @@
PROCESS_AUX_CHANNEL_TRANSACTION_PS_ALLOCATION args;
int index = GetIndexIntoMasterTable(COMMAND, ProcessAuxChannelTransaction);
unsigned char *base;
+ int retry_count = 0;
memset(&args, 0, sizeof(args));
base = (unsigned char *)rdev->mode_info.atom_context->scratch;
+retry:
memcpy(base, req_bytes, num_bytes);
args.lpAuxRequest = 0;
@@ -347,10 +349,12 @@
atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
- if (args.ucReplyStatus) {
- DRM_DEBUG("failed to get auxch %02x%02x %02x %02x 0x%02x %02x\n",
+ if (args.ucReplyStatus && !args.ucDataOutLen) {
+ if (args.ucReplyStatus == 0x20 && retry_count < 10)
+ goto retry;
+ DRM_DEBUG("failed to get auxch %02x%02x %02x %02x 0x%02x %02x after %d retries\n",
req_bytes[1], req_bytes[0], req_bytes[2], req_bytes[3],
- chan->rec.i2c_id, args.ucReplyStatus);
+ chan->rec.i2c_id, args.ucReplyStatus, retry_count);
return false;
}