[Nouveau] drm-nouveau-next - write trapped by fbcon

[Bruno Prémont]

Hi Ilia,

On Thu, 5 Dec 2013 10:55:06 -0500 Ilia Mirkin wrote:
> On Thu, Dec 5, 2013 at 10:17 AM, Bruno Prémont wrote:
> > With drm-nouveau-next branch on top of 3.13-rc2 and a few sound commits
> > I get following errors in kernel log (repeating much more often).
> > (once there was a corrupted fbcon with matrix-like strings of
> > unrecognizable glyph-strings hanging down from screen top border)
> >
> > These errors do stop once I switch to Xorg.
> >
> > [   13.825627] nouveau E[     PFB][0000:02:00.0] trapped write at 0x0000408280 on channel 0x0000fee0 [unknown] BAR/PFIFO_WRITE/FB reason: PAGE_NOT_PRESENT
> > [   13.826506] nouveau E[     PFB][0000:02:00.0] trapped write at 0x0000408280 on channel 0x0000fee0 [unknown] BAR/PFIFO_WRITE/FB reason: PAGE_NOT_PRESENT
> > [   13.827319] nouveau E[     PFB][0000:02:00.0] trapped write at 0x0000408280 on channel 0x0000fee0 [unknown] BAR/PFIFO_WRITE/FB reason: PAGE_NOT_PRESENT
> > [   13.828139] nouveau E[     PFB][0000:02:00.0] trapped write at 0x0000408280 on channel 0x0000fee0 [unknown] BAR/PFIFO_WRITE/FB reason: PAGE_NOT_PRESENT
> > [   13.828957] nouveau E[     PFB][0000:02:00.0] trapped write at 0x0000400300 on channel 0x0000fee0 [unknown] BAR/PFIFO_WRITE/FB reason: PAGE_NOT_PRESENT
> >
> > System MBA2,1 with:
> > 02:00.0 VGA compatible controller [0300]: NVIDIA Corporation C79 [GeForce 9400M] [10de:0870] (rev b1)
> 
> Do you also see these in 3.13-rc2 +
> http://cgit.freedesktop.org/nouveau/linux-2.6/commit/?h=drm-nouveau-next&id=a7e4201f0f7d47e03b851f06f8987856e8d33083
> ? If not, you can reorder the patches (git rebase -i) and bisect the
> rest. Basically the GPU is trying to write to some address that is
> either completely bogus or is stale, and its internal MMU won't let
> it.

If I remember correctly these did not happen with Linus' rc2 but only
do happen with drm-nouveau-next on top of it.

I will check and bisect though probably will not get time to complete
bisect before late Saturday.


A display glitch during kernel boot with fbcon might be related to this.
(very wild guess based on when the trapped writes happen)
The penguin logo shown by fbcon looks like memcopy'ed to a tiled
framebuffer without respecting the fact that framebuffer is tiled.


Bruno