dsp mmap change

Andriy Gapon avg at FreeBSD.org
Fri May 6 13:38:04 UTC 2011

on 06/05/2011 16:32 Kostik Belousov said the following:
> On Fri, May 06, 2011 at 11:55:00AM +0300, Andriy Gapon wrote:
>> I would like to ask for a review and/or testing of the following patch:
>> http://people.freebsd.org/~avg/dev_dsp_mmap.diff
>> It's supposed to fix an issue described here:
>> http://lists.freebsd.org/pipermail/freebsd-multimedia/2011-February/011691.html
>> In short, the following pseudo-code should do the right thing:
>> fd = open(/dev/dsp, O_RDWR);
>> mmap(PROT_READ, fd);
>> mmap(PROT_WRITE, fd);
>> Thank you!
> I think that you have to call PCM_GIANT_LEAVE() when returning
> EINVAL on the vm_pager_alloc() failure.

Yes, thank you.

> Your patch hardcodes an assumption that sndbufs are always
> contiguous. I was unable to convince myself that this is true.

I think that this should be true for the case when DMA is used?
But, yes, very good point.

Andriy Gapon

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