From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: [REANNOUNCE] Audio Mini Summit 2015, 8th October, Dublin Date: Mon, 27 Jul 2015 18:26:20 -0500 Message-ID: <55B6BE1C.50202@linux.intel.com> References: <20150714150352.GW11162@sirena.org.uk> <55A5330E.7000604@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by alsa0.perex.cz (Postfix) with ESMTP id 03B932658E5 for ; Tue, 28 Jul 2015 16:21:57 +0200 (CEST) In-Reply-To: <55A5330E.7000604@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: "Alexander E. Patrakov" , Mark Brown , Takashi Iwai , Liam Girdwood , Jaroslav Kysela Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org 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