[mythtv] [PATCH] Ticket #3598 MythFrontend doesn't work with some sound systems

[Wade Berrier]

Thanks for the response.

On 8/28/07, Stuart Morgan <stuart at tase.co.uk> wrote:
> On Tuesday 28 August 2007 10:46:19 Colin Guthrie wrote:
> > Wade Berrier wrote:
> > > Would someone mind committing the patch attached to this ticket?
> > >
> > > The patch is relatively simple, and has been verified by several people.
>
> It's waiting to be reviewed by a developer who knows the ALSA api, or is at
> least prepared to read up on it.

With ALSA, there are two sets of functions to get and push data to the
sound device: one that uses mmap, and one that doesn't.  The reason to
use mmap is for performance, but it's wrong to assume (as the alsa
output plugin does) that all devices support mmap.  (ie: a usb sound
device has no mmap support, as well as a software sound server like
PulseAudio that has alsa compatibility)

>
> There are plenty of patches in trac, all of them have to be reviewed and the
> order in which that happens entirely depends on the interests of the devs. If
> none of the devs are experiencing the non-mmap problems, then reading up on
> Alsa in order to properly review this patch isn't going to be a high
> priority.

Very few people will experience mmap issues, because any decent
card/driver will support it.  The point is, not all hardware or
software mixers do.

>
> How many people who aren't having problems have tested the patch? Has it been
> verified by a few people who aren't having any ALSA problems currently? I'd
> be more concerned that it breaks things for the majority if I were to even
> consider committing it without full review.

For me, it's worked for 3 different soundcards.  Meaning, ALSA worked
without the patch.  With the patch, native alsa worked, as well as the
pulseaudio alsa plugin.

Anyone else?

It looks like James Knight is the original author of the alsa plugin.
Maybe he can confirm this fix? (Hopefully the address I've CC'd is the
right one)  Or, someone else who is familiar with alsa?

Wade