[Intel-gfx] [PATCH 2/8] drm/i915: add the FBC mutex

[Paulo Zanoni]

2015-06-30 11:25 GMT-03:00 Chris Wilson <chris at chris-wilson.co.uk>:
> On Tue, Jun 30, 2015 at 10:53:06AM -0300, Paulo Zanoni wrote:
>> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
>>
>> Make sure we're not going to have weird races in really weird cases
>> where a lot of different CRTCs are doing rendering and modesets at the
>> same time.
>>
>> With this change, we can start removing the struct_mutex locking we
>> have around FBC in the next patches. The only struct_mutex requirement
>> will be around intel_fbc_update(), since it's the place that does the
>> CFB stolen memory allocations.
>>
>> v2:
>>  - Rebase (6 months later)
>>  - Also lock debugfs and stolen.
>> v3:
>>  - Don't lock a single value read (Chris).
>>  - Replace lockdep assertions with WARNs (Daniel).
>>  - Improve commit message.
>>  - Don't forget intel_pre_plane_update() locking.
>>
>> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
>
> I haven't spotted anything scary, but I only did a cursory scan of the
> patch for errors, and not down a delve into each function looking for
> trouble.

Thanks for the reviews! I'll add the ABBA comment and introduce a new
patch for the struct_mutex removal you spotted.

>
> Can I pretty please ask that you split fbc out of i915_gem_stolen.c
> before this patch (rather than teach stolen more about fbc)?

Ok, I'll do it.

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



-- 
Paulo Zanoni