[Intel-gfx] [PATCH] drm/i915: fix user irq miss in BSD ring on g4x

[Feng, Boqun]

Thanks for your advice. Maybe my patch log fail to _clearly_ show that there are
_two_ differences about irq control interface between gen4 and gen5

> -----Original Message-----
> From: Keith Packard [mailto:keithp at keithp.com]
> Sent: Friday, May 13, 2011 11:08 PM
> To: Feng, Boqun; intel-gfx at lists.freedesktop.org
> Cc: stable at kernel.org
> Subject: Re: [Intel-gfx] [PATCH] drm/i915: fix user irq miss in BSD ring on g4x
> 
> On Tue,  3 May 2011 12:42:24 +0800, "Feng, Boqun" <boqun.feng at intel.com>
> wrote:
> > On g4x, user interrupt in BSD ring is missed.
> > g4x and ironlake share the same bsd_ring, but their interrupt control
> > interfaces are different. On g4x i915_enable_irq and i915_disable_irq
                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1st, on gen5, we use ironlake_enable_irq and ironlake_disable_irq

> > are used to enable/disable irq,and user interrupt flag in BSD ring on
> > g4x is I915_BSD_USER_INTERRUPT.
        ~~~~~~~~~~~~~~~~~~~~~~~

2nd, on gen5, we use GT_BSD_USER_INTERRUPT

> > The ring_get_irq and ring_put_irq use ironlake style interrupt control
> > interface. So rather than use them, expand their code and add an if-else
> > statement about the device version.
> 
> Please don't open-code ring_get_irq here. I'd suggest a cleaner fix
> would be to either just conditionally call ring_get_irq, or to stick the
> BSD interrupt value in dev_priv where you can get it:
> 
>         if (IS_G4X(dev))
>                 ring_get_irq(ring, I915_BSD_USER_INTERRUPT);
>         else
>                 ring_get_irq(ring, GT_BSD_USER_INTERRUPT);
> 

So, we can't simply conditionally call ring_get_irq, we need to add a
conditionally call in ring_get_irq, too:
        if(is_G4X(dev))
                i915_enable_irq(ring, flag);
        else
                ironlake_enable_irq(ring, flag);

That's why I want to open-code ring_get_irq.

> or
>         ring_get_irq(ring, dev_priv->bsd_user_interrupt);
> 
> --
> keith.packard at intel.com

--
Feng, Boqun