On Wed, Apr 20, 2022 at 09:58:06AM +0000, Codrin.Ciubotariu@xxxxxxxxxxxxx wrote: > On 20.04.2022 12:15, Sascha Hauer wrote: > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > > > Hi, > > Hi Sascha, > > > > > On Mon, Mar 07, 2022 at 02:21:57PM +0200, Codrin Ciubotariu wrote: > >> Even if struct snd_dmaengine_pcm_config is used, prepare_slave_config() > >> callback might not be set. Check if this callback is set before using it. > >> > >> Fixes: fa654e085300 ("ASoC: dmaengine-pcm: Provide default config") > >> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@xxxxxxxxxxxxx> > >> --- > >> > >> Changes in v2,v3: > >> - none > >> > >> sound/soc/soc-generic-dmaengine-pcm.c | 6 +++--- > >> 1 file changed, 3 insertions(+), 3 deletions(-) > >> > >> diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c > >> index 285441d6aeed..2ab2ddc1294d 100644 > >> --- a/sound/soc/soc-generic-dmaengine-pcm.c > >> +++ b/sound/soc/soc-generic-dmaengine-pcm.c > >> @@ -86,10 +86,10 @@ static int dmaengine_pcm_hw_params(struct snd_soc_component *component, > >> > >> memset(&slave_config, 0, sizeof(slave_config)); > >> > >> - if (!pcm->config) > >> - prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config; > >> - else > >> + if (pcm->config && pcm->config->prepare_slave_config) > >> prepare_slave_config = pcm->config->prepare_slave_config; > >> + else > >> + prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config; > >> > >> if (prepare_slave_config) { > >> int ret = prepare_slave_config(substream, params, &slave_config); > > > > I wonder if this patch is correct. There are drivers like > > sound/soc/mxs/mxs-pcm.c which call snd_dmaengine_pcm_register() with a > > config which has the prepare_slave_config callback unset. For these > > drivers dmaengine_pcm_hw_params() previously was a no-op. Now with this > > patch snd_dmaengine_pcm_prepare_slave_config() and > > dmaengine_slave_config() are called. At least for the mxs-pcm driver > > calling dmaengine_slave_config() will return -ENOSYS. > > > > At least the "Check if this callback is set before using it" part is > > wrong, the callback is checked before using it with > > > > if (prepare_slave_config) { > > ... > > } > > > > I don't have any mxs hardware at hand to test this. I just stumbled upon > > the change of behaviour when rebasing > > https://patchwork.kernel.org/project/alsa-devel/patch/20220301122111.1073174-1-s.hauer@xxxxxxxxxxxxxx/ > > on current master. > > You are right. I changed the behavior from: > if (pmc->config && !pcm->config->prepare_slave_config) > <do nothing> > to: > if (pmc->config && !pcm->config->prepare_slave_config) > snd_dmaengine_pcm_prepare_slave_config() > > It was not intended and I agree that the commit message is not accurate. > I guess some drivers might not need dmaengine_slave_config()... > However, in my case, for the mchp-pdmc driver, I do have pcm->config > with pcm->config->prepare_slave_config NULL, but I still need > snd_dmaengine_pcm_prepare_slave_config() to be called. Should we add a > separate flag to call snd_dmaengine_pcm_prepare_slave_config() if > pcm->config->prepare_slave_config is NULL? Other drivers set pcm->config->prepare_slave_config to snd_dmaengine_pcm_prepare_slave_config() explicitly: sound/soc/fsl/imx-pcm-dma.c:33: .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config, I think that's the way to go. Regards, Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |