[Patch 0/1]drm_irq: Introducing the irq_thread support

[Liu, Chuansheng]

> Well, you cant use the pre_install/post_install hooks the drm_irq code provides,
> but yes, just do the request_irq in your driver code at the right time, with the
> right parameters. Much easier than adding code to a part of the drm core
> fraught with backwards-compat stuff no one really wants to touch ... All the
> additional stuff besides calling request_irq and the driver hooks that
> drm_irq_install does is really just to support old dri1 userspace.
> 
Please have a look for the patch, I just added the callback of irq thread handler, default is NULL without set,
So it should be no impact with others.

In case irq threadler func is NULL, it equals to request_irq, thanks.