Re: [REANNOUNCE] Audio Mini Summit 2015, 8th October, Dublin

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 7/14/15 11:04 AM, Alexander E. Patrakov wrote:
> 14.07.2015 20:03, Mark Brown wrote:
>> Like previous years, we're going to hold a meeting to discuss
>> lowlevel audio on Linux.  This will be held the day after ELC Europe on
>> 8th October at CCD (The Convention Centre) in Dublin.
>>
>> If you're interested please sign up in the attendee list:
>>
>> https://docs.google.com/spreadsheets/d/1bi-8GHsqlzt41FR20WiMuWILe_cZowFireVMBd-QM8Q/edit?usp=sharing
>>
>>
>> and please follow up to this mail with any topics you'd like to see
>> raised so we can start collecting them (probably another Google doc will
>> be forthcoming for them).
>
> I would like to see some direct measurements related to recent
> power-saving proposals, including the "disable rewinds" flag. Myself, I
> can redo battery-life measurements on Intel-based laptops that my
> colleagues have, and maybe compare dmix, PulseAudio and CRAS in terms of
> power consumption.
>
> Ideally, I would like to reevaluate the design decisions (namely, the
> need to keep the system responsive to new streams while keeping the
> average wakeup rate as low as possible, IMHO even to the point of
> "absurdly low") that led to the need to support rewinds (and the
> associated complexity) in the first place. Reminder: on my Sony VAIO
> VPC-Z23A4R laptop and hw:0 device, in an unrealistic test with the
> screen turned off, wi-fi turned off, and the SSDs put to sleep, going
> from 200 to 1 wakeup per second saved only 935 seconds of battery life
> out of 25742.

I had more success that you in my experiments a long time ago, but this 
really depends on what the rest of the system does.
You have a point though that we should talk about design decisions for 
userspace code. The current PulseAudio implementation lags behind the 
capabilities of newer devices with two or more outputs (low-latency, 
increased buffering and hardware/firmware mixing). This should really be 
a topic following the presentation of the HDAudio/Asoc restructuring 
that Vinod mentioned (i.e. how to change userspace code to support 
driver capabilities).
-Pierre