Re: another control API issue

[Abramo Bagnara <abramo@alsa-project.org>]

Paul Davis wrote:
> 
> >I expected something similar. Don't you think that to have a FLOAT type
> >is a better choice (more card independent, more accessible, more
> >representative, etc.).
> 
> Well, that was my initial thought. Then I remembered that we can't
> have floating point code in the kernel, and its therefore unsafe to
> even use this data type (an interrupt in kernel mode doesn't result in
> an FP register restore, and we may have run another task in the
> meantime that used the FP registers before we get back to our code).
> 
> In this particular case, even if it was safe to store the value in a
> float, the actual float value has to be computed with FP math, which
> is definitely not available in the kernel. so it wouldn't help much
> here.
> 
> Sound right?

Not fully. You can use FPU in kernel space with some attention (disable
preemption and save/restore FPU state for critical area).

-- 
Abramo Bagnara                       mailto:abramo@alsa-project.org

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It sounds good!

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