On Friday 21 March 2008 12:53:40 Hannu Savolainen wrote:
> Btw, you may also periodically (every 5-10 sec) check state of the
> SNDCTL_MIXERINFO->enabled field for all existing mixers. This field will
> change to false when an USB (or whatever) mixer is unplugged and back to
> true when the device gets replugged. If the mixer is not enabled then
> the tab for it could be disabled.
>
> However this probably makes things far too complicated. The program will
> probably call some mixer ioctl before next poll and just exit because
> the call returned ENXIO. Another approach is to check availability of a
> mixer device if any ioctl call suddenly returns ENXIO.
The other ossxmix polling function only poll the currently shown mixer
device - so ossxmix can't wait for ENXIO. It has to use a separate polling
function to check whether the other devices are still alive, or more devices
were added.
There's an interesting condiion where a device is added but another one is
removed within the 5 second polling.
I don't have the hardware to test, but if I understand correctly:
A) Removing a mixer device does not affect the numbering of the remaining
devices unless 'ossdevlinks -r' is run.
B) The newly added device does not use the same number as the old one.
C) SYSINFO->nummixers is incremented anyway after this is done, since the
old number remain as a 'ghost'.
Yours,
Yair K.
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