Hi! Noticed an intermittent flicker of the monitor (part goes black for a fraction of a second) with kernel 4.4.10. dmesg showed the following messages: [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun [drm:ironlake_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun Bisected it to this commit: > git bisect bad 8e1001c5638e244ab9a2ddddf5466b05ddf6af77 is the first bad commit commit 8e1001c5638e244ab9a2ddddf5466b05ddf6af77 Author: Shashank Sharma <shashank.sharma@intel.com> Date: Thu Apr 21 16:48:32 2016 +0530 drm/i915: Fake HDMI live status commit 60b3143c7cac7e8d2ca65c0b347466c5776395d1 upstream. This patch does the following: - Fakes live status of HDMI as connected (even if that's not). While testing certain (monitor + cable) combinations with various intel platforms, it seems that live status register doesn't work reliably on some older devices. So limit the live_status check for HDMI detection, only for platforms from gen7 onwards. V2: restrict faking live_status to certain platforms V3: (Ville) - keep the debug message for !live_status case - fix indentation of comment - remove "warning" from the debug message (Jani) - Change format of fix details in the commit message Fixes: 237ed86c693d ("drm/i915: Check live status before reading edid") Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1461237606-16491-1-git-send-email-shashank.sharma@intel.com Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (cherry picked from commit 4f4a8185011773f7520d9916c6857db946e7f9d1) Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> :040000 040000 6e90ff06fc964d1ddbb57155f8a42b840ea563d9 f76dff57b7ea8aa4d8cd66544eefc0a0b6c37a3d M drivers --- Regards! Jay
Reversing that patch did *not* resolve the problem in 4.4.10. Tough luck!
(In reply to Jay from comment #1) > Reversing that patch did *not* resolve the problem in 4.4.10. > Tough luck! The bisect result looked suspicious anyway.
(In reply to Jani Nikula from comment #2) > (In reply to Jay from comment #1) > > Reversing that patch did *not* resolve the problem in 4.4.10. > > Tough luck! > > The bisect result looked suspicious anyway. OK, I was wrong: it's also there in 4.4.9, 4.4 and 4.4.16 (the latest). The whole 4-series is probably affected. So it was introduced with or prior to 4.4. I have a dual-monitor-setup and I found out that I can reproduce it reliably by moving the mouse between the two monitors (when bisecting, only one monitor was on). Seems that 4.6.4 is *not* affected. HTH.
(In reply to Jay from comment #3) > (In reply to Jani Nikula from comment #2) > > (In reply to Jay from comment #1) > > > Reversing that patch did *not* resolve the problem in 4.4.10. > > > Tough luck! > > > > The bisect result looked suspicious anyway. > > OK, I was wrong: it's also there in 4.4.9, 4.4 and 4.4.16 (the latest). The > whole 4-series is probably affected. Damn! I mean 4.4 series, of course.
(In reply to Jani Nikula from comment #2) > (In reply to Jay from comment #1) > > Reversing that patch did *not* resolve the problem in 4.4.10. > > Tough luck! > > The bisect result looked suspicious anyway. Perhaps you like this one better: > git bisect good 43d59eda1f69631c267e06ab6b94ed3c14f1f6d1 is the first bad commit commit 43d59eda1f69631c267e06ab6b94ed3c14f1f6d1 Author: Matt Roper <matthew.d.roper@intel.com> Date: Thu Sep 24 15:53:07 2015 -0700 drm/i915: Eliminate usage of plane_wm_parameters from ILK-style WM code (v2) Just pull the info out of the plane state structure rather than staging it in an additional structure. v2: Add 'visible' condition to sprites_scaled so that we don't limit the WM level when the sprite isn't enabled. (Ville) Signed-off-by: Matt Roper <matthew.d.roper@intel.com> Reviewed-by(v1): Ander Conselvan de Oliveira <conselvan2@gmail.com> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> :040000 040000 b11db95f066a752dcccb0082490eabf21f62e8db 88bc02171246d693a868cd9ddb3144ee5d9b0ea8 M drivers 4.2, 4.3, 4.3.6 were all good. So I bisected between 4.3 and 4.4. The patch is a huge thing that I cannot easily reverse. That's one for you. ;)
Please try v4.5 or try cherry-picking commit 48e1d903f3e6b7fbb53142f24f9f35ae2c91b864 Author: Matt Roper <matthew.d.roper@intel.com> Date: Mon Feb 8 11:05:28 2016 -0800 drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2) to v4.4.
(In reply to Jani Nikula from comment #6) > Please try v4.5 or try cherry-picking > > commit 48e1d903f3e6b7fbb53142f24f9f35ae2c91b864 > Author: Matt Roper <matthew.d.roper@intel.com> > Date: Mon Feb 8 11:05:28 2016 -0800 > > drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2) > > to v4.4. Seems we had the same idea: saw your mail *after* I had already solved it. ;) Applied commit e2e407dc093f530b771ee8bf8fe1be41e3cea8b3 Author: Matt Roper <matthew.d.roper@intel.com> Date: Mon Feb 8 11:05:28 2016 -0800 drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2) Due to our lack of two-step watermark programming, our driver has ... to 4.4.16 and the flicker is gone, all else is fine so far. How shall we proceed? 4.4 is a longterm kernel and openSuse is going to use it for its upcoming Leap 42.2 (I think).
I sent the stable backport request, Cc: you. The bug is fixed upstream, we don't track stable backports here, as it's out of our hands. Closing as fixed.
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