From mboxrd@z Thu Jan 1 00:00:00 1970 From: stefan@agner.ch (Stefan Agner) Date: Wed, 15 Feb 2017 14:44:12 -0800 Subject: sDMA on i.mx7d In-Reply-To: <20170215110736.oumvvv7zordd2jdw@piout.net> References: <20170214222425.hbkfkeq3l6sveo7n@piout.net> <20170215110736.oumvvv7zordd2jdw@piout.net> Message-ID: <3513b2c01d86ad7312522d6be97e766f@agner.ch> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2017-02-15 03:07, Alexandre Belloni wrote: > On 14/02/2017 at 23:25:34 -0800, Stefan Agner wrote: >> On 2017-02-14 14:24, Alexandre Belloni wrote: >> > Hi, >> > >> > I've been trying to get a PCM3168s codec with a Colibri iMX7 using TDM >> > on SAI2. >> > I've got it working properly with the 4.1.35 kernel from Toradex (based >> > on the 4.1.15 from Freescale). >> > It is working fine with and without providing a firmware to the sDMA. >> > >> > But, I couldn't get that to work with v4.9. I actually managed to >> > reproduce the issue using the SGTL5000 so I don't have any patch on top >> > of v4.9. >> >> I guess you are using the on module SGTL5000 to reproduce? >> > > Yes, using the on module sgtl5000 of a colibri on an iris. > >> When I added audio support I remember that the sound seemed to be ok to >> me. Is the corruption such that you can hear it? >> > > You can hear it but not if you are playing a simple sine at a frequency > that is a multiple of 10 (e.g. 440Hz) > Compiled v4.9 and played a song, I could clearly hear constant "noise" during playback. I went back to my v4.8-rc3 + some patches applied back when I tested audio and submitted the device tree change, and the noise isn't there. In a "I feel lucky" manor I just reverted the last patch 5881826ded79 ("dmaengine: imx-sdma - update the residue calculation for cyclic channels") and the song sounded clean as always again! Alexandre, does reverting this helps your issue too? +Nandor, Author of said patch. Any idea? -- Stefan