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| author | Matthew Auld <matthew.auld@intel.com> | 2016-10-19 23:29:53 +0200 |
|---|---|---|
| committer | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2016-10-21 15:09:22 +0200 |
| commit | d4cb3fd9b548b8bfe2a712ec920b9ebabd3547ab (patch) | |
| tree | c2e9462d4d5b74c8cafec6174dd0de81affaa04e /drivers | |
| parent | drm/i915: Fix whitespace issues (diff) | |
| download | linux-d4cb3fd9b548b8bfe2a712ec920b9ebabd3547ab.tar.xz linux-d4cb3fd9b548b8bfe2a712ec920b9ebabd3547ab.zip | |
drm/i915/dp: add lane_count check in intel_dp_check_link_status
Currently it's entirely possible to go through the link training step
without first determining the lane_count, which is silly since we end up
doing a bunch of aux transfers of size = 0, as highlighted by
WARN_ON(!msg->buffer != !msg->size), and can only ever result in a
'failed to update link training' message. This can be observed during
intel_dp_long_pulse where we can do the link training step, but before
we have had a chance to set the link params. To avoid this we add an
extra check for the lane_count in intel_dp_check_link_status, which
should prevent us from doing the link training step prematurely.
v2: add WARN_ON_ONCE and FIXME comment (Ville)
References: https://bugs.freedesktop.org/show_bug.cgi?id=97344
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1476912593-10019-1-git-send-email-matthew.auld@intel.com
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index e03e79f7714a..f30db8f2425e 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -4041,6 +4041,11 @@ intel_dp_check_link_status(struct intel_dp *intel_dp) if (!to_intel_crtc(intel_encoder->base.crtc)->active) return; + /* FIXME: we need to synchronize this sort of stuff with hardware + * readout */ + if (WARN_ON_ONCE(!intel_dp->lane_count)) + return; + /* if link training is requested we should perform it always */ if ((intel_dp->compliance_test_type == DP_TEST_LINK_TRAINING) || (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count))) { |