lkml.org 
[lkml]   [2014]   [Aug]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: 3.15-rc: regression in suspend
On Fri, 11 Jul 2014, Pavel Machek wrote:

> > > > Ok, so I have set up machines for ktest / autobisect, and found out that
> > > > 3.16-rc1 no longer has that problem. Oh well, bisect would not be fun,
> > > > anyway...
> > >
> > > I am still seeing the problem with 3.16-rc2.
> >
> > I'm confused now. Is the bisect result
> >
> > commit 773875bfb6737982903c42d1ee88cf60af80089c
> > Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Date: Mon Jan 27 10:00:30 2014 +0100
> >
> > drm/i915: Don't set the 8to6 dither flag when not scaling
> >
> > now the culprit or not? Or do we have 2 different bugs at hand here?
>
> Three different issues, it seems. Two ring initialization problems,
> one went away in 3.16 (for me), second did not (suspend for jikos),
> third -- trivial issue with 8to6 dither.

The patch below seems to finally cure the problem at my system; I've just
attached it to freedesktop bugzilla, but sending it to this thread as well
to hopefully get as much testing coverage by affected people as possible.

I am going on with testing whether it really completely fixes the problem
or just made it less likely.





From: Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH] drm/i915: read HEAD register back in init_ring_common() to enforce ordering

Withtout this, ring initialization fails reliabily during resume with

[drm:init_ring_common] *ERROR* render ring initialization failed ctl 0001f001 head ffffff8804 tail 00000000 start 000e4000

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 279488a..7add7ee 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -517,6 +517,9 @@ static int init_ring_common(struct intel_engine_cs *ring)
else
ring_setup_phys_status_page(ring);

+ /* Enforce ordering by reading HEAD register back */
+ I915_READ_HEAD(ring);
+
/* Initialize the ring. This must happen _after_ we've cleared the ring
* registers with the above sequence (the readback of the HEAD registers
* also enforces ordering), otherwise the hw might lose the new ring
--
Jiri Kosina
SUSE Labs


\
 
 \ /
  Last update: 2014-08-07 15:01    [W:0.085 / U:1.148 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site