Re: [Intel-gfx] [git pull] drm fixes

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Mar 25, 2015 at 11:37:35AM -0400, Josh Boyer wrote:
> On Wed, Mar 25, 2015 at 10:00 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
> > On Wed, Mar 25, 2015 at 09:11:17AM -0400, Josh Boyer wrote:
> >> On Wed, Mar 25, 2015 at 4:54 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
> >> >> >> commit f55548b5af87ebfc586ca75748947f1c1b1a4a52
> >> >> >> Author: Damien Lespiau <damien.lespiau@intel.com>
> >> >> >> Date:   Thu Feb 5 18:30:20 2015 +0000
> >> >> >>
> >> >> >>     drm/i915: Don't try to reference the fb in get_initial_plane_config()
> >> >> >>
> >> >> >> From linux-next?
> >> >> >
> >> >> > Yes, building now.  Will let you know as soon as I test it on both machines.
> >> >>
> >> >> OK, with that commit applied I no longer get the kref.h splat and the
> >> >> NUC machine boots headless.  I still see the backtrace below on both
> >> >> the NUC and the macbook.  I have a copy of it with drm.debug=0xff from
> >> >> the NUC here:
> >> >>
> >> >> https://jwboyer.fedorapeople.org/pub/nuc-drm-debug-ff-with-fixes.txt
> >> >>
> >> >> Getting better at least :).
> >> >
> >> > On top of what you currently have please also cherry-pick
> >> >
> >> > commit fb9981aa675eb7b398849915364916fd98833cfa
> >> > Author: Damien Lespiau <damien.lespiau@intel.com>
> >> > Date:   Thu Feb 5 19:24:25 2015 +0000
> >> >
> >> >     drm/i915: Fix atomic state when reusing the firmware fb
> >> >
> >> > from -next. Let's hope this terminates eventually ;-)
> >>
> >> Hm.  That one doesn't apply cleanly.  I think because it needs:
> >>
> >> From 2d14030b1a9d0e89cfdca6f16851e2eac8cb4de0 Mon Sep 17 00:00:00 2001
> >> From: Damien Lespiau <damien.lespiau@intel.com>
> >> Date: Thu, 5 Feb 2015 17:22:18 +0000
> >> Subject: drm/i915: Store the initial framebuffer in initial_plane_config
> >>
> >> first.  Do you want me to grab both, or should I try and figure out
> >> how to backport fb9981aa67 without it?
> >
> > Oops missed that. The active ingredient is setting crtc->primary->state->crtc like this:
> > -Daniel
> >
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 1c12262029fb..bfc14a6046ea 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -2439,6 +2439,7 @@ intel_find_plane_obj(struct intel_crtc *intel_crtc,
> >                 return;
> >
> >         if (intel_alloc_plane_obj(intel_crtc, plane_config)) {
> > +               intel_crtc->base.primary->state->crtc = &intel_crtc->base;
> >                 update_state_fb(intel_crtc->base.primary);
> >                 return;
> >         }
> > @@ -2469,6 +2470,7 @@ intel_find_plane_obj(struct intel_crtc *intel_crtc,
> >
> >                         drm_framebuffer_reference(c->primary->fb);
> >                         intel_crtc->base.primary->fb = c->primary->fb;
> > +                       intel_crtc->base.primary->state->crtc = &intel_crtc->base;
> >                         obj->frontbuffer_bits |= INTEL_FRONTBUFFER_PRIMARY(intel_crtc->pipe);
> >                         break;
> >                 }
> 
> Hm.  So I used your patch above.  The macbook boots fine and all the
> oops/WARNS are gone except the audio one that was unrelated and
> present before all of this.
> 
> However, the NUC is back to not booting without HDMI plugged in.  I
> did the drm.debug=0xff+blacklist/insmod trick again and put the
> results up here:
> 
> https://jwboyer.fedorapeople.org/pub/vetters.txt
> 
> The frontbuffer splat is back now.
> 
> I confirmed multiple times that the NUC boots fine with the kernel
> that doesn't include the above patch but has the other two included
> (albeit with the drm_atomic WARN still).
> 
> Not sure what to make of this one.

Yeah that fail looks like we're freeing an fb that's still in use.
Hilarity happens and since that happens under console_lock at boot-up your
machine dies.

Does that machine die the same way in drm-intel-nightly/linux-next?

I'll try to figure out meanwhile what's amiss here ...
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch