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From: Arnd Bergmann <arnd@arndb.de>
To: Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC PATCH 4/6] Make DRM use the tasklet is-sched API
Date: Fri, 22 Jun 2007 18:10:55 +0200
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Cc: Daniel Walker <dwalker@mvista.com>, Steven Rostedt <rostedt@goodmis.org>,
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On Friday 22 June 2007, Thomas Gleixner wrote:
> > > Index: linux-2.6.21-rt9/drivers/char/drm/drm_irq.c
> > > ===================================================================
> > > --- linux-2.6.21-rt9.orig/drivers/char/drm/drm_irq.c
> > > +++ linux-2.6.21-rt9/drivers/char/drm/drm_irq.c
> > > @@ -461,7 +461,7 @@ void drm_locked_tasklet(drm_device_t *de
> > > ????static DECLARE_TASKLET(drm_tasklet, drm_locked_tasklet_func, 0);
> > > ?
> > > ????if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ) ||
> > > -??? ? ?test_bit(TASKLET_STATE_SCHED, &drm_tasklet.state))
> > > +??? ? ?tasklet_is_scheduled(&drm_tasklet))
> > > ????????????return;
> > > ?
> > > ????spin_lock_irqsave(&dev->tasklet_lock, irqflags);
> > > 
> > 
> > 
> > No sense in having a patch just for this, may as well merge this with
> > patch 3 ..
> 
> Wrong. patch 3 adds the API and this one makes use of it. Stevens split
> makes perfectly sense.

Wouldn't the easy solution be to get rid of drm_locked_tasklet
entirely and convert i915_vblank_tasklet(), the only user, to use
a work queue right away?

The drm_locked_tasklet() function seems to have multiple bugs anyway,
so getting rid of it can only help, and it avoids exporting a new
tasklet_is_scheduled() interface.

	Arnd <><
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