From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 00C053C8 for ; Fri, 31 Jul 2015 12:22:31 +0000 (UTC) Received: from atrey.karlin.mff.cuni.cz (atrey.karlin.mff.cuni.cz [195.113.26.193]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 3F73EED for ; Fri, 31 Jul 2015 12:22:29 +0000 (UTC) Date: Fri, 31 Jul 2015 14:22:27 +0200 From: Pavel Machek To: Mark Brown Message-ID: <20150731122227.GA31877@amd> References: <20150723105726.GC30929@amd> <20150723121441.GB29747@amd> <20150723084251.54da2be0@gandalf.local.home> <20150723202901.GA30318@amd> <20150729133244.GH20130@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150729133244.GH20130@sirena.org.uk> Cc: "ksummit-discuss@lists.linuxfoundation.org" , riverful.kim@samsung.com, kyungmin.park@samsung.com, John Stultz , Bjorn Andersson Subject: Re: [Ksummit-discuss] [CORE TOPIC] Mainline kernel on a cellphone List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed 2015-07-29 14:32:44, Mark Brown wrote: > On Thu, Jul 23, 2015 at 10:29:02PM +0200, Pavel Machek wrote: > > > 4) voice link to modem: Nokia people tell us that ALSA is not suitable > > interface to modem audio. What is the right interface, then? > > ALSA is the right interface for this, this is going to be some > misunderstanding on their part about how to use it or limitations in That's what I was arguing, but see https://lkml.org/lkml/2015/3/5/606 . kai> Our take was that ALSA is not the right interface for cmt_speech. The kai> cmt_speech interface in the modem is _not_ a PCM interface as modelled kai> by kai> ALSA. Specifically: kai> kai>- the interface is lossy in both directions kai>- data is sent in packets, not a stream of samples (could be other kai>- things kai> than PCM samples), with timing and meta-data kai> - timing of uplink is of utmost importance > the drivers for their particular system (and possibly some unfortunate > hardware design, it sounds like they may still be bouncing the voice > call through the AP which isn't the most wonderful idea ever). > There Actually, sending data through AP is _very_ good idea from security perspective. You don't want hacked baseband to eavesdrop on you, do you? Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html