Re: [patch 2.6.24-rc2 1/3] generic gpio -- gpio_chip support

From: David Brownell
Date: Tue Nov 13 2007 - 14:22:58 EST


On Tuesday 13 November 2007, Ingo Molnar wrote:
>
> * David Brownell <david-b@xxxxxxxxxxx> wrote:
>
> > > > I speculate that either the design has changed (without fanfare),
> > > > or else that stuff is in RT kernels and has not yet gone upstream.
> > >
> > > Well whatever. We shouldn't have to resort to caller-side party
> > > tricks like this to get acceptable performance.
> >
> > I'd be happy if, as originally presented, it were possible to just
> > pass a raw_spinlock_t to spin_lock_irqsave() and friends.
>
> that's a spinlock type abstraction of PREEMPT_RT, not of mainline.

Any reason that stuff shouldn't move into mainline?


> Why do you want to use raw_spinlock_t?

Already answered elsewhere in this thread ... I'll highlight the
point that such bitops shouldn't be preemption points.
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