Commit b6836227 authored by Daniel Vetter's avatar Daniel Vetter Committed by Jani Nikula

drm/i915: More cautious with pch fifo underruns

Apparently PCH fifo underruns are tricky, we have plenty reports that
we see the occasional underrun (especially at boot-up).

So for a change let's see what happens when we don't re-enable pch
fifo underrun reporting when the pipe is disabled. This means that the
kernel can't catch pch fifo underruns when they happen (except when
all pipes are on on the pch). But we'll still catch underruns when
disabling the pipe again. So not a terrible reduction in test
coverage.

Since the DRM_ERROR is new and hence a regression plan B would be to
revert it back to a debug output. Which would be a lot worse than this
hack for underrun test coverage in the wild. See the referenced
discussions for more.

References: http://mid.gmane.org/CA+gsUGRfGe3t4NcjdeA=qXysrhLY3r4CEu7z4bjTwxi1uOfy+g@mail.gmail.com
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85898
References: https://bugs.freedesktop.org/show_bug.cgi?id=85898
References: https://bugs.freedesktop.org/show_bug.cgi?id=86233
References: https://bugs.freedesktop.org/show_bug.cgi?id=86478Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Tested-by: default avatarlu hua <huax.lu@intel.com>
Reviewed-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent 009d0431
...@@ -4325,7 +4325,6 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc) ...@@ -4325,7 +4325,6 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
ironlake_fdi_disable(crtc); ironlake_fdi_disable(crtc);
ironlake_disable_pch_transcoder(dev_priv, pipe); ironlake_disable_pch_transcoder(dev_priv, pipe);
intel_set_pch_fifo_underrun_reporting(dev, pipe, true);
if (HAS_PCH_CPT(dev)) { if (HAS_PCH_CPT(dev)) {
/* disable TRANS_DP_CTL */ /* disable TRANS_DP_CTL */
...@@ -4389,7 +4388,6 @@ static void haswell_crtc_disable(struct drm_crtc *crtc) ...@@ -4389,7 +4388,6 @@ static void haswell_crtc_disable(struct drm_crtc *crtc)
if (intel_crtc->config.has_pch_encoder) { if (intel_crtc->config.has_pch_encoder) {
lpt_disable_pch_transcoder(dev_priv); lpt_disable_pch_transcoder(dev_priv);
intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_A, true);
intel_ddi_fdi_disable(crtc); intel_ddi_fdi_disable(crtc);
} }
......
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