[Intel-gfx] [PATCH 02/11] drm/i915: Clarify event_lock locking, irq&mixed context

[Jike Song]

On 09/29/2014 08:20 PM, Daniel Vetter wrote:
> On Mon, Sep 29, 2014 at 02:20:27PM +0800, Jike Song wrote:
>> On 09/15/2014 08:55 PM, Daniel Vetter wrote:
>>> Now we tackle the functions also called from interrupt handlers.
>>>
>>> - intel_check_page_flip is exclusively called from irq handlers, so a
>>>    plain spin_lock is all we need. In i915_irq.c we have the convention
>>>    to give all such functions an _irq_handler postfix, but that would
>>>    look strange and als be a bit a misleading name. I've opted for a
>>>    WARN_ON(!in_irq()) instead.
>>
>> Hi Daniel,
>>
>>   Is it possible to use in_interrupt() instead? Sorry to tell that, in
>> our iGVT-g implementation, the host i915 irq handler needs to be called
>> in a non hardirq driven context. i.e. a tasklet or workqueue.
>
> Hm, why that? Depending upon how you do this you might break a lot of the
> interrupt related locking we have ... This is a crucial integration issue,
> which patch does that change?
> -Daniel

The RFC patch set is not sent out yet, hopefully in 1~2 days :)

Yes I know it's not a good implementation ... I also wish there would be
a better way to go :)


--
Thanks,
Jike