[Intel-gfx] [PATCH] drm/i915: Check that the plane points to the pipe's framebuffer before enabling

[Jesse Barnes]

On Sun, 17 Apr 2011 10:32:41 +0100
Chris Wilson <chris at chris-wilson.co.uk> wrote:

> Knut Petersen reported a GPU hang when he left x11perf running
> overnight. The error state quite clearly indicates that plane A was
> enabled without being fully setup:
> 
> PGTBL_ER: 0x00000010
>     Display A: Invalid GTT PTE
> Plane [0]:
>   CNTR: c1000000
>   STRIDE: 00000c80
>   SIZE: 03ff04ff
>   POS: 00000000
>   ADDR: 00000000
> 
> [That GTT offset on his system being pinned for the ringbuffer.]
> 
> This is a simple debugging patch to assert that this cannot be so!
> 

I like it (though now the comment talks about DSPADDR and leaves
DSPSURF out in the cold).

Sounds like our dpms code may be causing trouble for this x11perf run
perhaps?  What else would cause us to change base addrs during a bench
run like that?

-- 
Jesse Barnes, Intel Open Source Technology Center