Re: [PATCH] drm/i915: add missing forcewake put on i915_wa_registers()

Ville Syrjälä
2014-10-22T07:36:07Z

On Tue, Oct 21, 2014 at 07:40:35PM +0200, Daniel Vetter wrote:
> On Tue, Oct 21, 2014 at 02:58:08PM -0200, Paulo Zanoni wrote:
> > From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> >
> > Otherwise, a simple "cat" to the debugfs file can make the machine use
> > much more power than needed, and prevent it from runtime suspending.
> >
> > Related commit:
> >
> > commit 8452e1d173a16d9812422a2272c4ab0f0ba81057
> > Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
> > Date: Tue Oct 7 17:21:26 2014 +0300
> > drm/i915: Build workaround list in ring initialization
> >
> > Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
> > Cc: Arun Siluvery <arun.siluvery@linux.intel.com>
> > Testcase: igt/pm_rpm/debugfs-read
> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
>
> tbh I'm not even sure we want to do the manual forcewake get here -
> I915_READ will do it for us, and this is a debug interface. So no one
> should care about perf. Mika, is that right? If so I'd like to merge the
> inverse patch which drops the fw_get.

Don't we still need the idle msg disable+poll CSPWRFSM trick here on
gen8? That also needs forcewake around it.

> -Daniel
>
> > ---
> > drivers/gpu/drm/i915/i915_debugfs.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> > index 9600285..36a4baa 100644
> > --- a/drivers/gpu/drm/i915/i915_debugfs.c
> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> > @@ -2671,6 +2671,7 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
> > addr, value, mask, read, ok ? "OK" : "FAIL");
> > }
> >
> > + gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
> > intel_runtime_pm_put(dev_priv);
> > mutex_unlock(&dev->struct_mutex);
> >
> > --
> > 2.1.1
> >
> > _______________________________________________
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> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Ville Syrjälä
Intel OTC