[Intel-gfx] i915 resume-from-hibernation problems on resume with current Linus' tree

[Jiri Kosina]

On Mon, 10 Mar 2014, Jiri Kosina wrote:

> > >> > *ERROR* render ring initialization failed ctl 0001f001 head 00003004 tail 00000000 start 00003000
> > >> >
> > >> > as it doesn't seem to be there in case of resumption that works properly.
> > >> >
> > >> > Please see the dmesg from the broken case below.
> > >>
> > >> I encountered this again with -rc5.
> > >>
> > >> If there is anything I can do to help debug this, please let me know.
> > >
> > > I hate to be doing this, but ... ping? :)
> > 
> > gm45 and rendering ring init failures. We've seen this occasionally
> > crop up due to rather unrelated changes. Some even hit stable
> > backports and had to be backed out again. We essentially have no clue
> > what's amiss, but it seems to /mostly/ work. Thus far I've only hear
> > reports of this for gm45 and not yet really for upstream. Until
> > someone digs up more evidence I think we need to classify this as a
> > rare heisenbug and not really a regression :(
> 
> Thanks for getting back to me with this, Daniel.
> 
> Well, this started to be rather regular sometime during the 3.14 
> development cycle on my system.
> 
> I am able to reproduce it after ~20 suspend-resume cycles. Which is rather 
> inconvenient for bisect, but enough for making the kernel unusable on that 
> system.
> 
> > One thing we could try is to simply repeat the ring init setup, maybe
> > after a gpu reset or something like that.
> 
> Will be happy to test any patches.

So I am still seeing this with current Linus' tree rather regularly (but 
it's not deterministic enough for a reliable bisect).

Unfortunately I haven't received any patches to test; what do you propose?
Would reporting this on bugs.freedesktop.org instead of ranting here 
change anything?

Thanks,

-- 
Jiri Kosina
SUSE Labs