[alsa-devel] ASoC: sgtl5000: SMALL_POP and loud click noise 5 secs after playback stopped
Hi,
since commit b101acfabc9377469af3abfb7cb63112da367284 I can hear a loud click / pop noise, always occuring 5 seconds after playback stopped.
Hardware: i.MX6Q board with SGTL5000 Kernel: 4.7-rc2 master
In the commit history of sgtl5000.h I saw that SGTL5000_SMALL_POP was previously 0 and that Fabio, who changed it to 0, had a similar problem back then. Now with SGTL5000_SMALL_POP at 1, the problem reappeared. Changing it back to 0 fixes the problem for me, but as Axel Lin explained in the commit mentioned above, having 0 as mask leads to not writing anything to the CHIP_REF_CTRL register and the SMALL_POP bit stays as it was.
So why does this help?
Maybe having SMALL_POP active causes that noise in some circumstances? Then we could add a devicetree property to turn it on or off as needed.
Or, the documentation of the SMALL_POP bit in the datasheet is not correct / inverted? Then we could remove that write to the CHIP_REF_CTRL register and leave the SMALL_POP bit at its default value?
Axel: Did changing SGTL5000_SMALL_POP to 1 remove a click/pop noise on your board or did you just notice the error with the mask argument of snd_soc_update_bits and fixed it?
Thanks, Clemens
On Tue, Jun 07, 2016 at 12:00:26AM +0200, Clemens Gruber wrote:
since commit b101acfabc9377469af3abfb7cb63112da367284 I can hear a loud click / pop noise, always occuring 5 seconds after playback stopped.
Please include human readable descriptions of things like commits and issues being discussed in e-mail in your mails, this makes them much easier for humans to read especially when they have no internet access. I do frequently catch up on my mail on flights or while otherwise travelling so this is even more pressing for me than just being about making things a bit easier to read.
Axel: Did changing SGTL5000_SMALL_POP to 1 remove a click/pop noise on your board or did you just notice the error with the mask argument of snd_soc_update_bits and fixed it?
I would be very surprised if Axel has one of these boards, he does a lot of cleanup work based on code/datasheet analysis. I suspect it's more likely that the chip feature simply doesn't work properly and we're better off not using it.
participants (2)
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Clemens Gruber
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Mark Brown