Hi Eric, Fabio, Mark,
On Sat, Jun 04, 2016 at 07:15:25PM +0200, Clemens Gruber wrote:
please don't merge the patch yet, I just observed a strange effect when resetting the board during playback / just after playback stops. At next boot time, sometimes the following error occurs: imx-sgtl5000 sound: ASoc: CODEC DAI sgtl5000 not registered imx-sgtl5000 sound: snd_soc_register_card failed (-517)
I looked into this today and discovered the following:
With my patch applied, if I reset the board just after playback, at the next boot, the sgtl5000_fill_defaults function does not succeed: Writing the default value 0x7060 to register 0x30 (CHIP_ANA_POWER) fails.
How did CHIP_ANA_POWER change with my patch: Before, only LINREG_SIMPLE_POWERUP was cleared as is recommended in the datasheet when using the internal LDO, now both LINREG_SIMPLE_POWERUP and STARTUP_POWERUP are cleared, as is recommended when using external VDDD.
But why does the SGTL5000 nack that default write to CHIP_ANA_POWER after a reboot, which interrupted the playback?
The following patch from Eric solved the problem; one write fails but it continues setting the other registers and thus even if resetting a board during playback, the sound still works after reboot: http://mailman.alsa-project.org/pipermail/alsa-devel/2015-February/088356.ht... Another workaround might be to not even write a default value to CHIP_ANA_POWER, as in this patch from Eric: http://mailman.alsa-project.org/pipermail/alsa-devel/2015-February/088355.ht...
What do you think we should do?
Regards, Clemens