This is a note to let you know that I've just added the patch titled
drm/i915: More cautious with pch fifo underruns
to the 3.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-more-cautious-with-pch-fifo-underruns.patch
and it can be found in the queue-3.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b68362278af94e1171f5be9d4e44988601fb0439 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@xxxxxxxx>
Date: Mon, 24 Nov 2014 17:02:45 +0100
Subject: drm/i915: More cautious with pch fifo underruns
From: Daniel Vetter <daniel.vetter@xxxxxxxx>
commit b68362278af94e1171f5be9d4e44988601fb0439 upstream.
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@xxxxxxxxxxxxxx
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=86478
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Tested-by: lu hua <huax.lu@xxxxxxxxx>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_display.c | 2 --
1 file changed, 2 deletions(-)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4209,7 +4209,6 @@ static void ironlake_crtc_disable(struct
ironlake_fdi_disable(crtc);
ironlake_disable_pch_transcoder(dev_priv, pipe);
- intel_set_pch_fifo_underrun_reporting(dev, pipe, true);
if (HAS_PCH_CPT(dev)) {
/* disable TRANS_DP_CTL */
@@ -4274,7 +4273,6 @@ static void haswell_crtc_disable(struct
if (intel_crtc->config.has_pch_encoder) {
lpt_disable_pch_transcoder(dev_priv);
- intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_A, true);
intel_ddi_fdi_disable(crtc);
}
Patches currently in stable-queue which might be from daniel.vetter@xxxxxxxx are
queue-3.17/drm-i915-unlock-panel-even-when-lvds-is-disabled.patch
queue-3.17/drm-i915-more-cautious-with-pch-fifo-underruns.patch
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