[pulseaudio-discuss] [PATCH] Change the default fragment size to 5 ms

[Alexander E. Patrakov]

24.10.2014 00:08, Andrew Eikum wrote:
> On Thu, Oct 23, 2014 at 10:57:18PM +0530, Arun Raghavan wrote:
>> On 23 October 2014 22:46, Alexander E. Patrakov <patrakov at gmail.com> wrote:
>>> 22.10.2014 22:21, I wrote:
>>>>
>>>> Of course, this only applies to ALSA devices that can't use tsched, as
>>>> well as to OSS on more exotic platforms.
>>>>
>>>> This is needed for compatibility with Wine games that use DirectSound8
>>>> on distributions such as Arch Linux who don't accept the unofficial
>>>> winepulse patch. The reason is that Wine DirectSound8 emulation requests
>>>> a period of 10 ms and expects it to work for the purposes of timing. And
>>>> in fact, it cannot know (via ALSA API) that it is not going to work!
>>>
>>>
>>> I hereby withdraw the patch, as on IRC I see that Arun said:
>>>
>>> """
>>> I'm not too happy with changing that. It would affect CPU on systems that
>>> don't care about Wine.
>>> and I really really don't want to work around bad clients in PA. (despite
>>> the fact that I am also bitten by this bug)
>>> ...
>>> Want to start a BrokenClients page?
>>> """
>>>
>
> It's true that Wine's audio doesn't get much work these days, though
> in my defense :) it's a time issue, not a willingness issue.
>
> I have spent literally weeks trying to understand and work around the
> timing issues that cause problems with USB devices accessed with the
> PulseAudio ALSA plugin. I plan to continue working on it, but business
> priorities lay elsewhere at the moment and I've already spent loads of
> time on it.
>
>>> (note: due to the "cannot know" reason, I still disagree that it is a
>>> client-side problem)
>>
>> I've not looked at the Wine code for this, but I wonder if we can
>> guess this by looking at the minreq/tlength values that are returned.
>>
>
> I'd love to work with an ALSA/PA expert to come up with a solution,
> either by fixing Wine or coming up with a new ALSA API to provide the
> info we need.
>
> I have a patch in-hand which improves the current driver
> significantly, but it isn't enough to fix the USB devices problem. If
> someone wants to review the winealsa driver with the patch applied and
> discuss solutions, let me know. I'd love to get this problem solved.

If you send me the patch, I promise to have a look at it. But, see my 
other reply why there cannot be a full solution within the ALSA API.

-- 
Alexander E. Patrakov