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

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

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
> _______________________________________________
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-- 
Ville Syrjälä
Intel OTC