Re: [PATCH v2] drm/i915: Also perform gpu reset under execlist mode.

Zhi Wang
2015-07-07T12:26:43Z

Thanks! I had question about power context.

I was curious about HW context and once dumped the GEM context object on
GEN6 before.

According to B-spec, Gen Graphics » BSpec » 3D-Media-GPGPU Engine »
Registers in Render Engine » Render Logical Context Data » Register
State Context [SNB+] » Register State Context [HSW] »

I thought the context should contain all the register regions in the
list include the dark yellow marked registers as power context
registers, but I saw the content of the context I got began with main
context, LRI signature 110010bf. .. It's weird.

I don't know if the context saved by MI_SET_CONTEXT is just the power
context in B-spec?If yes, why doest it looks like that?

Thanks,
Zhi.

于 07/07/15 20:10, Chris Wilson 写道:
> On Tue, Jul 07, 2015 at 04:32:53AM +0800, Zhi Wang wrote:
>> Thanks for the comments!:) I'm wondering that why the GEN>=5 is
>> needed here. Is there any HW problems in GEN>=5 when driver wants to
>> do GPU reset? I'm sorry that I don't know much about GEN<6...Just
>> want to know more about the story:)
>
> gen5 is about the earliest that I know the hw stated to get smart and
> doing automatic power saving by writing to pinned buffers. Before gen5
> our reset hasn't been very reliable, and only recently have we had code
> that is meant to be able to reset the gpu on those gen - hence my
> reservation about doing so unconditionally.
> -Chris