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author | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2016-07-28 17:54:42 +0300 |
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committer | Dave Airlie <airlied@redhat.com> | 2016-07-29 14:13:03 +1000 |
commit | a1f5524a66ff6284d1380cdd7723de82698ff9d3 (patch) | |
tree | 1947ac50f8b1f44c2552faf0bae22b6a85d81873 /drivers/gpu/drm/drm_dp_helper.c | |
parent | 162b20d2f9ef9dfa833cc329b1e8957beb672349 (diff) | |
download | op-kernel-dev-a1f5524a66ff6284d1380cdd7723de82698ff9d3.zip op-kernel-dev-a1f5524a66ff6284d1380cdd7723de82698ff9d3.tar.gz |
drm: aux ->transfer() can return 0, deal with it
Restore the correct behaviour (as in check msg.reply) when aux
->transfer() returns 0. It got removed in
commit 82922da39190 ("drm/dp_helper: Retry aux transactions on all errors")
Now I can actually dump the "entire" DPCD on a Dell UP2314Q with
ddrescue. It has some offsets in the DPCD that can't be read
for some resaon, all you get is defers. Previously ddrescue would
just give up at the first unredable offset on account of
read() returning 0 means EOF. Here's the ddrescue log
for the interested:
0x00000000 0x00001400 +
0x00001400 0x00000030 -
0x00001430 0x000001D0 +
0x00001600 0x00000030 -
0x00001630 0x0001F9D0 +
0x00021000 0x00000001 -
0x00021001 0x000DEFFF +
Cc: Lyude <cpaul@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch
Cc: stable@vger.kernel.org
Fixes: 82922da39190 ("drm/dp_helper: Retry aux transactions on all errors")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
-rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 091053e..8f11b87 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -203,7 +203,7 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, ret = aux->transfer(aux, &msg); - if (ret > 0) { + if (ret >= 0) { native_reply = msg.reply & DP_AUX_NATIVE_REPLY_MASK; if (native_reply == DP_AUX_NATIVE_REPLY_ACK) { if (ret == size) |