drm/radeon/kms: fix regression in DP aux defer handling

An incorrect ordering in the error checking code lead
to DP aux defer being skipped in the aux native write
path.  Move the bytes transferred check (ret == 0)
below the defer check.

Tracked down by: Brad Campbell <brad@fnarfbargle.com>

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=41121

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Brad Campbell <brad@fnarfbargle.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 7ad43c6b1db7..f526fa77e320 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -158,14 +158,14 @@ static int radeon_dp_aux_native_read(struct radeon_connector *radeon_connector,
         while (1) {
                 ret = radeon_process_aux_ch(dig_connector->dp_i2c_bus,
                                             msg, msg_bytes, recv, recv_bytes, delay, &ack);
-                if (ret == 0)
-                        return -EPROTO;
                 if (ret < 0)
                         return ret;
                 if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK)
                         return ret;
                 else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
                         udelay(400);
+                else if (ret == 0)
+                        return -EPROTO;
                 else
                         return -EIO;
         }