[alsa-devel] [PATCH - alsa-lib 1/1] Change card/pid get functions to return -ENOSYS if the kernel is too old

[Adam Goode]

On Fri, Apr 1, 2016 at 1:33 PM, Adam Goode <agoode at google.com> wrote:

> When trying to get the pid or card of a client, the get functions will
> return -1 if there is no pid or card for a client. Clients have zero or
> one of these, so -1 is correct for these cases. But we also need to detect
> the case where the kernel cannot tell us if there is a card or pid, so
> that userspace can fallback to probing this information in the old way.
>


Also: Thanks Martin, for taking care of this! I wrote the seq/sysfs probing
code in Chromium and have been struggling to find the time to fix it up.
Now I've got no excuse. :)


Adam