[pulseaudio-discuss] [PATCH] Add HDMI Surround 7.1 profiles

David Henningsson david.henningsson at canonical.com
Wed Jul 16 08:40:55 PDT 2014

On 2014-07-16 16:40, Alexander E. Patrakov wrote:
> 16.07.2014 19:47, David Henningsson wrote:
>> So, given this the only place where extra 7.1 profiles actually take
>> some time to consider is this one (NVIDIA HDMI). Where adding 7.1
>> profiles to all four devices would probably lead to an additional
>> startup delay of 100 - 150 ms.
>> All other places we probably get stopped in userspace, which means less
>> than a ms delay.
> I have updated the patch, and found that around 100 ms get wasted
> reliably for something that is neither mapping_open_pcm() nor
> mapping_paths_probe() before probing surround21 on the USB headphones. I
> do not understand this phenomenon (might be a buggy patch due to the
> noise here).

profile_finalize_probing calls snd_pcm_close, which communicates with 
the hardware. Unless that is accounted for, I assume that could be the 
delays you're seeing.

> The new timing patch is attached, as well as the gzipped
> very-very-verbose log from that PC.

David Henningsson, Canonical Ltd.

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