Re: [Qemu-devel] [PATCH] Nowadays alsa and pulseaudio are most often the default soundsystem. When the headerfiles are found, enable the build of the alsa and pulseaudio audio driver for the default targetos.

[Peter Maydell <peter.maydell@linaro.org>]

On 1 May 2014 13:56, Sander Eikelenboom <linux@eikelenboom.it> wrote:
> Thursday, May 1, 2014, 1:06:35 PM, you wrote:
>> This is a lower-quality duplicate of the code we already
>> have in configure for probing whether an audio backend
>> is present (for instance it doesn't allow for the possibility
>> that the headers have been installed elsewhere). It would
>> be better to update the existing probe code to distinguish
>> between "must be present", "don't use" and "use if present"
>> for each audio driver, in the same way we do for other
>> features. Then we could just set the default list here
>> to "maybe-pa maybe-alsa oss" (syntax off the top of my
>> head, feel free to have a better idea).
>
> How bad would it be for the generic targetos case to start with:
>
> audio_drv_list == audio_possible_drivers = "oss alsa sdl esd pa"
>
> or just add the probably most used two:
> audio_drv_list = "oss alsa pa"
>
> and just let the auto probing do it's business ?

At the moment if you put something in audio_drv_list
then configure will stop with an error if that driver
can't be probed. So putting 'pa' or 'alsa' in the
default list is a bad idea, because people whose setups
worked fine for building qemu will suddenly find they
stop working.

We need both behaviours -- distributions want to be able
to say "build with pulseaudio" and have the build fail
if their pulseaudio dependencies aren't set up correctly
rather than silently produce a package which won't work
in their distro. But the average person building QEMU
for their own use generally would prefer "probe for the
features but if they're not present then just don't
build the code that uses them".

thanks
-- PMM