[lkml]   [2014]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 3.17 18/47] drm/i915: More cautious with pch fifo underruns
3.17-stable review patch.  If anyone has any objections, please let me know.


From: Daniel Vetter <>

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

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.

Signed-off-by: Daniel Vetter <>
Tested-by: lu hua <>
Reviewed-by: Paulo Zanoni <>
Signed-off-by: Jani Nikula <>
Signed-off-by: Greg Kroah-Hartman <>

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_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) {
- intel_set_pch_fifo_underrun_reporting(dev, TRANSCODER_A, true);

 \ /
  Last update: 2014-12-14 22:01    [W:0.353 / U:0.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site