From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lars-Peter Clausen Subject: Re: [alsa-devel] [PATCH v3 4/5] ASoC: tda998x: adjust the audio hw parameters from EDID Date: Wed, 05 Feb 2014 10:19:22 +0100 Message-ID: <52F2021A.9020804@metafoo.de> References: <1b15025671d9099863a3091346536e45891e4a26.1391274628.git.moinejf@free.fr> <20140204180625.GM22609@sirena.org.uk> <20140205101134.4591e5c3@armhf> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140205101134.4591e5c3@armhf> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org To: Jean-Francois Moine Cc: alsa-devel@alsa-project.org, Russell King - ARM Linux , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Mark Brown , linux-arm-kernel@lists.infradead.org List-Id: alsa-devel@alsa-project.org On 02/05/2014 10:11 AM, Jean-Francois Moine wrote: > On Tue, 4 Feb 2014 18:06:25 +0000 > Mark Brown wrote: > >> On Mon, Jan 27, 2014 at 09:48:54AM +0100, Jean-Francois Moine wrote: >> >>> + /* change the snd_soc_pcm_stream values of the driver */ >>> + stream->rates = rate_mask; >>> + stream->channels_max = max_channels; >>> + stream->formats = formats; >> >>> + /* copy the DAI driver to a writable area */ >>> + dai_drv = devm_kzalloc(&pdev->dev, sizeof(tda998x_dai), GFP_KERNEL); >>> + if (!dai_drv) >>> + return -ENOMEM; >>> + memcpy(dai_drv, tda998x_dai, sizeof(tda998x_dai)); >>> + >> >> The code should be doing this by setting constraints based on the >> current setup rather than by editing the data structure - the expecation >> is very much that the data won't change so this prevents surprises with >> future work on the core. > > As it is done in the soc core, in soc_pcm_open(), the runtime hw_params > are initialized after the call to the CODEC startup, and the next CODEC > event is hw_params() when the user has already chosen all the parameters. > > So, in the CODEC, I don't see how I could update the parameters > dictated by the EDID otherwise in changing the DAI driver parameters. > The startup function is the right place. But instead of modifying the DAI use snd_pcm_hw_constraint_mask64(), snd_pcm_hw_constraint_list(), etc. to setup the additional constraints that come from the EDID. Bonus points for making this a generic helper function that takes a runtime and a EDID and then applies the EDID constraints on the runtime. - Lars