[Bug 71701] Regression, Dual-Head, i915 mode-setting driver, "pipe B stuck"

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=71701

--- Comment #27 from Kris Karas <bugs-a13 at moonlit-rail.com> ---
I just finished bisecting drm-intel-nightly to see what it is that makes it
"work" in my case.  Seems that waiting for vblank at the right moments is the
solution.   I backported the commit into mainline 3.14.0 and it fixed the
problem for me.  In any case, here it is:

>From be6a6f8ec707f2e446e445ad4b8cc93cc85d5d54 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter at ffwll.ch>
Date: Tue, 15 Apr 2014 18:41:22 +0200
Subject: [PATCH] drm/i915: Don't vblank wait on ilk-ivb after pipe enable
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Like on hsw/bdw the pipe isn't actually running yet at this point.              
This holds for both pch ports and the cpu edp port according to my              
testing on ilk, snb and ivb.                                                    

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77297                    
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>                      
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>                           
---                                                                             
 drivers/gpu/drm/i915/intel_display.c | 14 ++++----------                       
 1 file changed, 4 insertions(+), 10 deletions(-)

-- 
You are receiving this mail because:
You are on the CC list for the bug.