Re: [PATCH 12/19] drm/i915: release the GTT mmaps when going into D3

Paulo Zanoni
2013-11-21T16:27:30Z

2013/11/21 Chris Wilson <chris@chris-wilson.co.uk>:
> On Thu, Nov 21, 2013 at 01:47:26PM -0200, Paulo Zanoni wrote:
>> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
>>
>> So we'll get a fault when someone tries to access the mmap, then we'll
>> wake up from D3.
>
> Harsh. Very harsh. Is the GTT completely off-limits under pc8

Under D3, not PC8.

> , or is it
> only the GTT access to the display engine? i.e. could we get away with
> only killing some of the mmaps?

I don't have any documentation describing what should work and what
shouldn't: all I know comes from our test suite, function
gem_mmap_subtest:
http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/tree/tests/pm_pc8.c#n927
. On that test, we don't use the buffers on the display engine. We
just do gem_create(), then gem_mmap__gtt(), write values to the buff,
put the device in D3, then try to read the buffer contents and see if
it is what we wrote. So I imagine the answer to your question is
probably "no".

If you have more ideas of tests I could write that would help
answering your questions, please tell me:)

> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre

--
Paulo Zanoni