From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Grab RPM wakeref around enabling vblank interrupts
Date: Fri, 7 Oct 2016 21:44:53 +0300 [thread overview]
Message-ID: <20161007184453.GZ4329@intel.com> (raw)
In-Reply-To: <20161007183300.GV22676@nuc-i3427.alporthouse.com>
On Fri, Oct 07, 2016 at 07:33:00PM +0100, Chris Wilson wrote:
> On Fri, Oct 07, 2016 at 09:06:07PM +0300, Ville Syrjälä wrote:
> > On Fri, Oct 07, 2016 at 02:50:32PM +0100, Chris Wilson wrote:
> > > Whilst the vblank is configured to send an interrupt everytime, we need
> > > to keep the device awake to process those interrupts.
> >
> > If we can enable vblanks the pipe will be active, and thus we can't
> > runtime suspend anyway. Also might_sleep() would be a problem.
>
> Where is the pipe made active? Is it just having any mode is sufficient
> to disable rpm? Will that always be the case?
Active pipe holds a power domain reference, which implies an rpm
reference as well.
>
> Just tracing from the drm_wait_vblank ioctl to the mmio access it didn't
> occur to me that there was a crtc wakeref.
>
> Choice is either using something like intel_runtime_pm_get_noresume() or
> /* CRTC must be kept alive whilst we enable vblanks */
> assert_rpm...()
>
> And possibly even using the seq check.
> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
--
Ville Syrjälä
Intel OTC
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next prev parent reply other threads:[~2016-10-07 18:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 13:50 [PATCH] drm/i915: Grab RPM wakeref around enabling vblank interrupts Chris Wilson
2016-10-07 18:06 ` Ville Syrjälä
2016-10-07 18:33 ` Chris Wilson
2016-10-07 18:44 ` Ville Syrjälä [this message]
2016-10-07 18:57 ` Chris Wilson
2016-10-07 19:00 ` Chris Wilson
2016-10-07 19:17 ` Ville Syrjälä
2016-10-10 10:19 ` ✗ Fi.CI.BAT: warning for " Patchwork
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