[Intel-gfx] [PATCH 3/5] drm/i915/contexts: Switch to default on resume

[Ben Widawsky]

On 2012-08-15 02:18, Chris Wilson wrote:
> On Tue, 14 Aug 2012 14:35:15 -0700, Ben Widawsky <ben at bwidawsk.net> 
> wrote:
>> In order to make the HW state CCID match with what we think it 
>> should
>> be, we must order a switch to the default context.
>>
>> The really sad thing here is that the switch can potentially fail, 
>> and
>> as such we have to assume contexts no longer work. There is likely 
>> room
>> for improvement but until we actually start seeing the case occur, I
>> think it should be fine.
>>
>> This was accidentally left this out of the first series, noticed by
>> Chris Wilson.
>
> However that do_switch() is a no-op as it spots that the
> ring->last_ctx_obj is the DEFAULT_CONTEXT (saved across s&r) and we 
> exit
> early.
>
> The only clean way I could see was to extract the actual set_switch
> portion of do_switch() (i.e. discard the initial checks and 
> pre-/post-op
> pinning). Which brings you nicely into the next few patches...
> -Chris

Agreed, I was thinking re-ordering the series would just magically 
solve all such issues :-)

-- 
Ben Widawsky, Intel Open Source Technology Center