From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaud Mouiche Subject: Re: [PATCH v2] ASoC: fsl_ssi: Fix channel swap on playback start Date: Tue, 4 Apr 2017 10:59:36 +0200 Message-ID: References: <1491058131-31366-1-git-send-email-festevam@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wr0-f173.google.com (mail-wr0-f173.google.com [209.85.128.173]) by alsa0.perex.cz (Postfix) with ESMTP id B0B012668F6 for ; Tue, 4 Apr 2017 10:59:38 +0200 (CEST) Received: by mail-wr0-f173.google.com with SMTP id t20so26312339wra.1 for ; Tue, 04 Apr 2017 01:59:38 -0700 (PDT) In-Reply-To: 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: Caleb Crome , Fabio Estevam Cc: "alsa-devel@alsa-project.org" , Sascha Hauer , Timur Tabi , Nicolin Chen , Mark Brown , Max Krummenacher , Fabio Estevam List-Id: alsa-devel@alsa-project.org So to summarize: - Caleb and I don't see the issue without the patch, but we are working on DSP mode @ 48K (mostly as master of the bus). But the patch break none trivial "playback only" cases. platforms: imx6 quad for Caleb, imx6sl for me. We are working without codec, checking the bit stream generated by one SSI by recording and checking the content using another SSI. - Fabio and Max experience the issue very easily in I2S mode, acting as slave (I guess otherwise generating precise 44.1Khz would be hard), connecting to a STGL5000 codec. When you are master of the bus, it is important to start EN before TE for the FIFO pre-fill reasons. The samples need to be ready as soon as TE starts. I also guess that ENGcm06222 doesn't affect us when the SSI is master (since the SSI is govern only by its own timing) As slave, this is less important to start EN before TE because you have little chance to receive the SYNC trigger as soon as EN+TE starts => the DMA did get time to fill the FIFO. Yet, as slave, ENGcm06222 affect the order of channels, as experienced by Fabio. So I switch on I2S mode for my SSI => SSI tests and, sadly, I didn't experience issues without the patch. I did the test on vanilla 4.11.0-rc5. which branch/repository are Fabio using for his tests ? The way clocks are configured may explain the difference: Dumping /sys/kernel/debug/clk/clk_summary and checking the differences can give some clues. In my case, I have, for the slave SSI #2, while the PCM bus is running at 48khz+I2Smode+2 channels. pll4 0 0 786432000 0 0 pll4_bypass 0 0 786432000 0 0 pll4_audio 0 0 786432000 0 0 pll4_post_div 0 0 786432000 0 0 pll4_audio_div 0 0 786432000 0 0 ssi2_sel 0 0 786432000 0 0 ssi2_pred 0 0 196608000 0 0 ssi2_podf 0 0 98304000 0 0 ssi2 0 0 98304000 0 0 Strangely, the 'enable_cnt' is kept equal to zero while the SSI transmit frames correctly... Is there a patch or a branch somewhere that fix this issue ? Also, here is a dump of SSI registers. /var/root # cat /sys/kernel/debug/regmap/202c000.ssi/registers 00: 00000000 04: 00000000 10: 0000105b 18: 009031a3 1c: 00000285 20: 00000205 24: 0004e100 28: 00040100 2c: 00880888 30: 00000000 34: 00000000 38: 00000000 48: fffffffc 4c: fffffffc 50: 00000000 54: 00000000 58: 00000000 Arnaud On 04/04/2017 01:42, Caleb Crome wrote: > On Mon, Apr 3, 2017 at 4:40 PM, Fabio Estevam wrote: >> Hi Caleb, >> >> On Mon, Apr 3, 2017 at 8:22 PM, Caleb Crome wrote: >> >>> With a vanilla kernel, it works perfectly with the pinctrl patch. >>> In this case, I ran a cable from the wandboard over to my computer and >>> recorded with audacity, using your wile true script above. >>> Here you can see that with 4.11-rc5 plus the pinctrl patch, there is >>> no channel swapping: >>> >>> http://imgur.com/od0LoJP >> Which wandboard type do you have? mx6solo,dl or quad? >> >> I am using imx6dl-wandboard. >> >> I am surprised that the channel swap does not happen on your case. >> Maybe you need to run the test for an extended period of time? > Running on a quad. > >> On my case I usually get the swap in 1/10 of times. Max uses a Toradex >> MX6DL Colibri board and sees the swap in 3-4% of the times. > I'll run it for a much longer time and see what happens.