Re: i915_driver_irq_handler: irq 42: nobody cared

From: "Michel Dänzer" <michel@daenzer.net>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Jiri Slaby <jslaby@suse.cz>, LKML <linux-kernel@vger.kernel.org>,
	Jiri Slaby <jirislaby@gmail.com>,
	dri-devel@lists.freedesktop.org
Subject: Re: i915_driver_irq_handler: irq 42: nobody cared
Date: Wed, 11 Apr 2012 08:29:22 +0200	[thread overview]
Message-ID: <1334125762.31776.4.camel@thor.local> (raw)
In-Reply-To: <20120410113448.540e4c1d@jbarnes-desktop>

On Die, 2012-04-10 at 11:34 -0700, Jesse Barnes wrote: 
> On Tue, 10 Apr 2012 20:11:29 +0200
> Jiri Slaby <jslaby@suse.cz> wrote:
> 
> > On 04/10/2012 06:26 PM, Jesse Barnes wrote:
> > > So port hotplug is always reporting that port C has a hotplug
> > > interrupt though...  If you write 0x3 back to it does the interrupt
> > > stop?
> > 
> > I'm not sure I got it right. This doesn't help:
> > --- a/drivers/gpu/drm/i915/i915_irq.c
> > +++ b/drivers/gpu/drm/i915/i915_irq.c
> > @@ -1416,6 +1416,17 @@ static irqreturn_t
> > i915_driver_irq_handler(DRM_IRQ_ARGS)
> >                 iir = new_iir;
> >         }
> > 
> > +       if (ret == IRQ_NONE) {
> > +               u32 hp = I915_READ(PORT_HOTPLUG_STAT);
> > +               if (hp) {
> > +                       I915_WRITE(PORT_HOTPLUG_STAT, hp);
> > +                       I915_READ(PORT_HOTPLUG_STAT);
> > +               }
> > +
> > +               if (printk_ratelimit())
> > +                       printk(KERN_DEBUG "%s: %.8x\n", __func__, hp);
> > +
> > +       }
> > 
> >         return ret;
> >  }
> 
> Yeah that looks right, you still get 0x300?

You said 'If you write 0x3 back' above, but this code writes 0x300.
Which is right?

-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer