[Intel-gfx] [PATCH] drm/i915: Disable DMC powersaving during GT operations

[Joonas Lahtinen]

+ Jari & Samu

On Tue, 2017-09-12 at 13:48 +0100, Chris Wilson wrote:
> Quoting Chris Wilson (2017-09-12 13:37:32)
> > diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
> > index 813a3b546d6e..3c8ebdb5b0b4 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_request.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_request.c
> > @@ -254,6 +254,9 @@ static void mark_busy(struct drm_i915_private *i915)
> >         intel_runtime_pm_get_noresume(i915);
> >         i915->gt.awake = true;
> >  
> 
> /*
>  * The DMC doesn't behave well when it is active (i.e the system is
>  * idle). It continually tries to toggle DC_STATE_EN causing a
>  * severe slow down of the rest of the system (severe enough to trigger
>  * watchdogs and reboot the machine under CI testing).
>  *
>  * Known affected firmware:
>  * - skl_dmc_ver1_26.bin
>  * - bxt_dmc_ver1_07.bin
>  */

Has this patch been tested more widely, does it have negative
performance effects?

Regards, Joonas

> > +       if (i915->csr.dmc_payload)
> > +               intel_display_power_get(i915, POWER_DOMAIN_MODESET);
> > +
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation