Re: [PATCH] snd-hda-intel: fix insufficient memory

[Andrew Morton <akpm@osdl.org>]

On Wed, 22 Nov 2006 18:19:49 +0100
wbrana@gmail.com wrote:

> Module uses shorter buffer if memory isn't sufficient.
> It doesn't change size of allocated memory automatically.
> User has to change it with command like this:
> echo 256 > /proc/asound/card0/pcm0p/sub0/prealloc
> I can change it, but many regular users don't know it.
> This card is used in new PCs, which have at least 256 MB RAM.
> 256 kB shouldn't be too much. Whole block isn't used if it isn't needed.

That didn't answer my question.

> On 11/22/06, Andrew Morton <akpm@osdl.org> wrote:
> > On Tue, 21 Nov 2006 21:33:29 +0100
> > wbrana@gmail.com wrote:
> >
> > > Module allocates insufficient memory for multichannel and high quality
> > > audio (96 kHz, 24 bit)
> > > Patch for 2.6.19-* changes default/maximal size from 64/128 to 256/4096 kB.
> > >
> > > --- sound/pci/hda/hda_intel.c.orig      2006-09-29 13:40:36.000000000 +0200
> > > +++ sound/pci/hda/hda_intel.c   2006-11-05 16:45:13.000000000 +0100
> > > @@ -1270,5 +1270,5 @@
> > >         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
> > >                                               snd_dma_pci_data(chip->pci),
> > > -                                             1024 * 64, 1024 * 128);
> > > +                                             1024 * 256, 1024 * 4096);
> > >         chip->pcm[pcm_dev] = pcm;
> > >         if (chip->pcm_devs < pcm_dev + 1)
> >
> > This was recently increased, but not by such a large amount:
> >
> >         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
> >                                               snd_dma_pci_data(chip->pci),
> >                                               1024 * 64, 1024 * 1024);
> >
> > is that sufficient?
> >

Are the new settings of 64kb and 1MB sufficient?  If not, by how much must
they be increased, and why?