linux-kernel - Re: i915_driver_irq_handler: irq 42: nobody cared

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Date:	Tue, 10 Apr 2012 11:48:06 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	daniel@...ll.ch, Jesse Barnes <jbarnes@...tuousgeek.org>,
	LKML <linux-kernel@...r.kernel.org>,
	dri-devel@...ts.freedesktop.org, Jiri Slaby <jirislaby@...il.com>,
	Chris Wilson <chris@...is-wilson.co.uk>
Subject: Re: i915_driver_irq_handler: irq 42: nobody cared

On 04/10/2012 10:58 AM, Daniel Vetter wrote:
> On Tue, Apr 10, 2012 at 10:47:49AM +0200, Jiri Slaby wrote:
>> On 04/09/2012 07:11 PM, Jesse Barnes wrote:
>>> On Fri, 30 Mar 2012 11:45:43 +0100 Chris Wilson
>>> <chris@...is-wilson.co.uk> wrote:
>>>
>>>> On Fri, 30 Mar 2012 11:59:28 +0200, Jiri Slaby <jslaby@...e.cz>
>>>> wrote:
>>>>> I don't know what to dump more, because iir is obviously zero
>>>>> too. What other sources of interrupts are on the (G33) chip?
>>>>
>>>> IIR is the master interrupt, with chained secondary interrupt
>>>> statuses. If IIR is 0, the interrupt wasn't raised by the GPU.
>>>
>>> I've actually seen cases where one of the PIPE*STAT regs is stuck,
>>> and even if IIR is 0 we still get interrupts... Jiri can you verify
>>> the PIPE*STAT regs have bits set, maybe one or more we don't check
>>> for?
>>
>> Note that I already attached their contents... This is what is in them
>> (pipes 0 and 1):
>> [ 3572.968581] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3572.977472] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3576.224839] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3576.243558] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3576.384912] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3576.403462] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3577.464100] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3577.477383] i915_driver_irq_handler: 0=00000000 1=00000000
>> [ 3577.829016] i915_driver_irq_handler: 0=00020000 1=00000000
>> [ 3577.830093] i915_driver_irq_handler: 0=00020000 1=00000000
>>
>> I.e. the handler is called when IIR=0 and both pipe stats are 0.
> 
> Hm, can you also dump the PORT_HOTPLUG_STAT register? That's the only
> other subordinate interrupt source left.

It's always 0x300:
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000
i915_driver_irq_handler: HP=00000300 0=00000000 1=00000000

thanks,
-- 
js
suse labs

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