Return-Path: Subject: Re: choosing SCO parameters at run time From: Marcel Holtmann To: Johan Hedberg Cc: takeiteasy , linux-bluetooth@vger.kernel.org In-Reply-To: <20100505223214.GA3699@jh-x301> References: <20100505223214.GA3699@jh-x301> Content-Type: text/plain; charset="UTF-8" Date: Thu, 06 May 2010 06:25:51 +0200 Message-ID: <1273119951.22838.298.camel@localhost.localdomain> Mime-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Johan, > > I have a question related to SCO packet path configuration for > > Bluetooth HSP/HFP profiles. As I understand, > > we need to use SCO routing option in etc/bluetooth/audio.conf to > > select the voice path to be over HCI or PCM. > > It seems the option is configured at the init time.Can I select PCM or > > HCI routing at runtime? > > That variable isn't intended to trigger a SCO routing change but to > simply tell BlueZ & Pulse Audio (or whatever audio subsystem you use) > what the hardware platforms configuration is. I.e. the actual routing of > your bluetooth controller needs to be configured separately (and afaik > there's no standard HCI command through which it could be done which > further promotes the idea that BlueZ shouldn't have any code for it). in theory this is possible and I know of a few chips that can change the routing before establishing the SCO link. However this is all highly vendor specific and needs extensive kernel and driver support. So while possible, I haven't seen it in practice at all. Especially with modern chips supports more than one SCO over PCM. Regards Marcel