omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!

[Peter Ujfalusi]

Hi,

On 20/07/2020 12.03, Peter Ujfalusi wrote:
> Hi,
> 
> On 14/07/2020 21.03, Jarkko Nikula wrote:
>> Hi
>>
>> On 7/11/20 6:33 AM, Dave Young wrote:
>>> Hi,
>>>
>>> I'm trying to use g_audio on my Nokia N900 with mainline kernel. Seems
>>> it does not work.  No sound when I play from a laptop, and also see a
>>> lot of error like below:
>>> [ 4729.557647] omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!
>>> ...
>>>
>> Head 0dc589da873b ("Merge tag 'iommu-fixes-v5.8-rc5' of
>> git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu") records and
>> plays fine here (arecord -f dat |aplay), although I see some of those
>> errors but don't hear any glitches etc.
>>
>> Peter, does above indicate a serious issue or is it perhaps a false
>> alarm on OMAP3 (no audible glitches)?
> 
> I need to dig out my n900 or beagleXM, but it is hard to believe it is
> not a result of a glitch.
> The DMA is triggered by McBSP and it should write exactly what McBSP
> expects to be receiving.
> 
> I can not recall any changes in the past years which would have
> introduced regressions in McBSP or the sDMA driver.

I have booted linux-next on my BeagleXM (OMAP3630, McBSP2 <-> twl4030)
and I don't see the TX overflow print.

I have checked element and threshold modes and it looks fine.
I'm not sure why we have TX Overflow printed on n900.

>> I believe you don't have some mixer knob on, N900 audio path is somewhat
>> complex and needs bunch of mixer switches and volumes to be set. I
>> attached my N900 mixer scripts for you to try.
> 
> This could be the reason for the silence, I have asoundrc files
> somewhere to restore a 'good' mixer config.
> 
>> Set first everything off:
>> ./aic34_scripts/shutdown.sh
>>
>> Then enable internal digital microphone and speakers:
>> ./aic34_scripts/dmic.sh
>> ./aic34_scripts/speakers.sh
>>
>> Hopefully these help you get going :-)
>>
> 
> - Péter
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki