Re: [PATCH 2/2] drm/i915: take a power domain reference while checking the HDMI live status

[Jani Nikula <jani.nikula@intel.com>]

On Fri, 20 Nov 2015, Imre Deak <imre.deak@intel.com> wrote:
> On Fri, 2015-11-20 at 11:54 +0200, Imre Deak wrote:
>> On Thu, 2015-11-19 at 21:17 +0200, Ville Syrjälä wrote:
>> > On Thu, Nov 19, 2015 at 09:13:04PM +0200, Imre Deak wrote:
>> > > On Thu, 2015-11-19 at 21:08 +0200, Ville Syrjälä wrote:
>> > > > On Thu, Nov 19, 2015 at 08:55:01PM +0200, Imre Deak wrote:
>> > > > > There are platforms that don't need the full GMBUS power
>> > > > > domain
>> > > > > (PCH, BXT) while others do (VLV/CHV). For optimizing this we
>> > > > > would need to add a new power domain, but it's not clear how
>> > > > > much
>> > > > > we
>> > > > > would benefit given the short time we hold the reference. So
>> > > > > for
>> > > > > now
>> > > > > let's keep things simple.
>> > > > 
>> > > > Actually on PCH platforms the gmbus domain means just just an
>> > > > rpm ref since the gmbus hw lives in the PCH.
>> > > 
>> > > Ah right.
>> > > 
>> > > > And IIRC on BXT gmbus lives in pw0 so same deal really.
>> > > 
>> > > It's in PW2 there. I'll fix the commit message.
>> > 
>> > Doh. Not sure where I got the PW0 zero idea. Maybe I confused gmbus
>> > with hpd. But yes, you're right about that.
>> > 
>> > > 
>> > > > And for vlv/chv we should just need the disp2d well, which
>> > > > is exactly what we get with the gmbus domain.
>> > > > 
>> > > > So I don't think there's actually anything to optimize here
>> > > > with current platforms.
>> > > > 
>> > > > Both patches look fine to me:
>> > > > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> 
>> Pushed 1/2 and 2/2 with the fixed commit message to dinq. Thanks for
>> the review.
>
> I just noticed that 2/2 fixes the following commit which is in v4.4-rc1 
> already:
>
> commit 237ed86c693d8a8e4db476976aeb30df4deac74b
> Author: Sonika Jindal <sonika.jindal@intel.com>
> Date:   Tue Sep 15 09:44:20 2015 +0530
>
>     drm/i915: Check live status before reading edid
>
> so AFAIU this should've gone through -fixes. Jani can you still apply
> it there?

Otherwise no problem but this has a dependency on

commit f0ab43e6c338896cadee64ced3fc30a5343890d9
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Mon Nov 9 16:48:19 2015 +0100

    drm/i915: Introduce a gmbus power domain

and didn't bother figuring out how deep the rabbit hole goes.

If you want this in -fixes, please either send a -fixes specific patch,
or see how many commits would need to be backported.

BR,
Jani.



-- 
Jani Nikula, Intel Open Source Technology Center
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