Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Azizul Hakim]

Dear altruists,

I'm writing a sound card driver based on ALSA API. My driver works
perfectly on Ubuntu 12.04, 13.10 and 14.04. There is no problem on how many
times I play a sound file using my driver. Everything works great. But same
driver has some issue on debian distribution.


I've been trying to test it on BeagleBone and during the first run the
driver works pretty well. But as soon as I play a second sound file, it
crash. I thought may be I did something wrong in releasing resources after
1st run. But so far from my debugging it looks like there is no problem
with resource release. Also same driver works on Ubuntu as many times as I
test. I even tested with the same sound file.  On debian, I get the
following message is kernel log-

Apr 23 20:26:41 beaglebone kernel: [  183.631905] ALSA
sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ trouble?)


It would be highly appreciated if I can get some suggestions on which
direction I should try to resolve this issue. Is there any known issue with
debian distribution or anyone faced similar kind of problem before?


Thanks
Azizul Hakim

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Azizul Hakim]

Any suggestion please?

On Sat, Jun 13, 2015 at 11:18 PM, Azizul Hakim <azizulfahim2002@gmail.com>
wrote:

> Dear altruists,
>
> I'm writing a sound card driver based on ALSA API. My driver works
> perfectly on Ubuntu 12.04, 13.10 and 14.04. There is no problem on how many
> times I play a sound file using my driver. Everything works great. But same
> driver has some issue on debian distribution.
>
>
> I've been trying to test it on BeagleBone and during the first run the
> driver works pretty well. But as soon as I play a second sound file, it
> crash. I thought may be I did something wrong in releasing resources after
> 1st run. But so far from my debugging it looks like there is no problem
> with resource release. Also same driver works on Ubuntu as many times as I
> test. I even tested with the same sound file.  On debian, I get the
> following message is kernel log-
>
> Apr 23 20:26:41 beaglebone kernel: [  183.631905] ALSA
> sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ trouble?)
>
>
> It would be highly appreciated if I can get some suggestions on which
> direction I should try to resolve this issue. Is there any known issue with
> debian distribution or anyone faced similar kind of problem before?
>
>
> Thanks
> Azizul Hakim
>

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Clemens Ladisch]

Azizul Hakim wrote:
> kernel: ALSA sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ trouble?)

This message means that the playback position did not advance.

This typically indicates that your driver did not actually start the
DMA, or that interrupts do not arrive correctly, or that your .pointer
callback is buggy.


Regards,
Clemens

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Azizul Hakim]

So I've three possible scenario:

Driver didn't start the DMA: Not sure how to track on this point. Any
suggestion?

Interrupt do not arrive correctly: Is this the hardware issue or ALSA
issue?

.pointer callback is buggy: It makes some sense to me but I'm confused
about it though. Will check on this point.

Thanks
Azizul Hakim wrote:
> kernel: ALSA sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ
trouble?)

This message means that the playback position did not advance.

This typically indicates that your driver did not actually start the
DMA, or that interrupts do not arrive correctly, or that your .pointer
callback is buggy.


Regards,
Clemens

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Clemens Ladisch]

Azizul Hakim wrote:
> Driver didn't start the DMA: Not sure how to track on this point. Any suggestion?
> Interrupt do not arrive correctly: Is this the hardware issue or ALSA issue?

These would imply that some your driver, or some code used by your driver,
did not configure the DMA/interrupt correctly.


Regards,
Clemens

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Liam Girdwood]

+ Peter for Beaglebone

On Wed, 2015-06-17 at 10:01 +0200, Clemens Ladisch wrote:
> Azizul Hakim wrote:
> > Driver didn't start the DMA: Not sure how to track on this point. Any suggestion?
> > Interrupt do not arrive correctly: Is this the hardware issue or ALSA issue?
> 
> These would imply that some your driver, or some code used by your driver,
> did not configure the DMA/interrupt correctly.

On beaglebone it may also be that the McBSP port clocking is not
configured correctly.

Liam

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Azizul Hakim]

Okay, its good to learn something new on every day. So how do I configure
McBSP port clocking? I'm very new on these things and was unable to find
any useful link on this point. :(

On Wed, Jun 17, 2015 at 5:05 AM, Liam Girdwood <
liam.r.girdwood@linux.intel.com> wrote:

> + Peter for Beaglebone
>
> On Wed, 2015-06-17 at 10:01 +0200, Clemens Ladisch wrote:
> > Azizul Hakim wrote:
> > > Driver didn't start the DMA: Not sure how to track on this point. Any
> suggestion?
> > > Interrupt do not arrive correctly: Is this the hardware issue or ALSA
> issue?
> >
> > These would imply that some your driver, or some code used by your
> driver,
> > did not configure the DMA/interrupt correctly.
>
> On beaglebone it may also be that the McBSP port clocking is not
> configured correctly.
>
> Liam
>
>

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Azizul Hakim]

I discovered one thing which lead me to believe something is wrong in my
*.pointer* callback. I would like to share it for expert suggestions.

So when a audio playback starts I initialize the buffer pointer to "0" in
the *.prepare* function. During my 1st playback the audio driver works
great, I see the *.pointer* function getting called a lot of times.

I update the buffer pointer  in the URB completion function. Here goes a
code segment from my URB completion function:

https://gist.github.com/azizulhakim/d24a36ef753f9a1536fa



And this is my *.pointer* function:

https://gist.github.com/azizulhakim/b15b002f74e77f88cd5a


Now during the 2nd playback, the driver initializes the buffer pointer to
"0" again inside the *.prepare* function. And then I see it calls the
*.pointer* function only once and afterwards stop with the error message *ALSA
sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ trouble?)*


So I stopped initializing the buffer pointer to "0" during the second
playback assuming that the buffer pointer should stay at the place it
stopped from previous playback. But that also didn't work for me. I get the
same error message. Note that same driver works on Ubuntu without any
problem and as many times as I want.


It would be really helpful if I get some suggestion from the given code. In
case you wonder, the full code is available here
<https://github.com/azizulhakim/beagleusb/blob/master/beagle-audio.c>

Thanks
Azizul


On Wed, Jun 17, 2015 at 10:53 AM, Azizul Hakim <azizulfahim2002@gmail.com>
wrote:

> Okay, its good to learn something new on every day. So how do I configure
> McBSP port clocking? I'm very new on these things and was unable to find
> any useful link on this point. :(
>
> On Wed, Jun 17, 2015 at 5:05 AM, Liam Girdwood <
> liam.r.girdwood@linux.intel.com> wrote:
>
>> + Peter for Beaglebone
>>
>> On Wed, 2015-06-17 at 10:01 +0200, Clemens Ladisch wrote:
>> > Azizul Hakim wrote:
>> > > Driver didn't start the DMA: Not sure how to track on this point. Any
>> suggestion?
>> > > Interrupt do not arrive correctly: Is this the hardware issue or ALSA
>> issue?
>> >
>> > These would imply that some your driver, or some code used by your
>> driver,
>> > did not configure the DMA/interrupt correctly.
>>
>> On beaglebone it may also be that the McBSP port clocking is not
>> configured correctly.
>>
>> Liam
>>
>>
>

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Takashi Sakamoto]

Hi,

On Jun 19 2015 13:32, Azizul Hakim wrote:
> Now during the 2nd playback, the driver initializes the buffer pointer to
> "0" again inside the *.prepare* function. And then I see it calls the
> *.pointer* function only once and afterwards stop with the error message *ALSA
> sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ trouble?)*

When you see this log with playback PCM application, it means that 'the 
application is running in blocking-mode (O_NONBLOCK) with 
no-period-wakeup mode, and the blocking continues during 10 seconds'.
(when period-size is too large, it continues longer than 10 seconds.)

The blocking mode is released by several cues, but in this case I think
we should focus on calling 'snd_pcm_period_elapsed()'. In ALSA PCM 
driver, calling this function changes PCM ringbuffer status, then 
releases the blocking state in some conditions.

Therefore, we can judge that your driver may call no 
'snd_pcm_period_elapsed()' because receiving no 'struct urb.complete()' 
callback.

I think you should check your 'beagleaudio_audio_start()' function and 
confirm whether it can set/release USB subsystem correctly.

Additionally, I reccomend you to use URB monitor in runtime to see your 
driver can transmit URBs in second playbacking. (In my memory, Wireshark 
has the functionality.)

> So I stopped initializing the buffer pointer to "0" during the second
> playback assuming that the buffer pointer should stay at the place it
> stopped from previous playback. But that also didn't work for me. I get the
> same error message. Note that same driver works on Ubuntu without any
> problem and as many times as I want.

The zero-reset is needed, I think.

In your driver, 'struct beagleaudio.snd_buffer_pos' and 'struct 
beagleaudio.snd_period_pos' are used to count the number of PCM frames 
in a period or a buffer.

They're an alternative representation of ALSA PCM rung-buffer status, 
and no need to keep the state in different PCM runtimes. It's good to 
reset them before PCM substream is running. (typically, done in 'struct 
snd_pcm_ops.prepare()' callback).

# I note that I'm not good at USB subsystem and USB Audio Device Class.
# My comments come from general knowledgement about ALSA PCM core.


Regards

Takashi Sakamoto

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Takashi Sakamoto]

On Jun 19 2015 14:56, Takashi Sakamoto wrote:
> The blocking mode is released by several cues, but in this case I think
> we should focus on calling 'snd_pcm_period_elapsed()'. In ALSA PCM
> driver, calling this function changes PCM ringbuffer status, then
> releases the blocking state in some conditions.

Oops. 'The blocking state is released by several cues,' is correct.


Takashi Sakamoto

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Clemens Ladisch]

Azizul Hakim wrote:
> So when a audio playback starts I initialize the buffer pointer to "0"
> in the *.prepare* function.

This is correct.

> https://gist.github.com/azizulhakim/d24a36ef753f9a1536fa
> https://gist.github.com/azizulhakim/b15b002f74e77f88cd5a

This is not; the code confuses bytes and frames.

When in doubt, give _all_ variables a "_bytes" or "_frames" suffix, and
check that _every_ access uses the correct units.


Regards,
Clemens

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Takashi Sakamoto]

On Jun 19 2015 14:56, Takashi Sakamoto wrote:>
> When you see this log with playback PCM application, it means
> that 'the application is running in blocking-mode (O_NONBLOCK) with
> no-period-wakeup mode

Oops, again.

'without non-period-wakeup mode' is correct...


# I'm a bit tired from the humidity in this rainy season...


Regards

Takashi Sakamoto

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Raymond Yau]

>
> I discovered one thing which lead me to believe something is wrong in my
> *.pointer* callback. I would like to share it for expert suggestions.
>
> So when a audio playback starts I initialize the buffer pointer to "0" in
> the *.prepare* function. During my 1st playback the audio driver works
> great, I see the *.pointer* function getting called a lot of times.
>
> I update the buffer pointer  in the URB completion function. Here goes a
> code segment from my URB completion function:
>
> https://gist.github.com/azizulhakim/d24a36ef753f9a1536fa
>
>
>
> And this is my *.pointer* function:
>
> https://gist.github.com/azizulhakim/b15b002f74e77f88cd5a
>
>
> Now during the 2nd playback, the driver initializes the buffer pointer to
> "0" again inside the *.prepare* function. And then I see it calls the
> *.pointer* function only once and afterwards stop with the error message
*ALSA
> sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ trouble?)*
>
>
> So I stopped initializing the buffer pointer to "0" during the second
> playback assuming that the buffer pointer should stay at the place it
> stopped from previous playback. But that also didn't work for me. I get
the
> same error message. Note that same driver works on Ubuntu without any
> problem and as many times as I want.
>
>
> It would be really helpful if I get some suggestion from the given code.
In
> case you wonder, the full code is available here
> <https://github.com/azizulhakim/beagleusb/blob/master/beagle-audio.c

Do your driver really support one period per buffer when you specify
.periods_min  = 1 ?

Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Peter Ujfalusi]

On 06/17/2015 05:53 PM, Azizul Hakim wrote:
> Okay, its good to learn something new on every day. So how do I configure
> McBSP port clocking? I'm very new on these things and was unable to find any
> useful link on this point. :(

I don't see anything in the driver [1] which would indicate that the issue is
in any ways specific to BeagleBone (apart from the beagleaudio strings in the
driver). You are not using the McASP, nor the edma-pcm/davinci-pcm.
What you seams to have is a custom sound card driver for USB. Is there a
reason why you could not use the already available USB sound card for this?

Are you running exactly the same kernel under ubuntu and debian?

-- 
Péter

[1] https://github.com/azizulhakim/beagleusb/blob/master/beagle-audio.c

> On Wed, Jun 17, 2015 at 5:05 AM, Liam Girdwood
> <liam.r.girdwood@linux.intel.com <mailto:liam.r.girdwood@linux.intel.com>> wrote:
> 
>     + Peter for Beaglebone
> 
>     On Wed, 2015-06-17 at 10:01 +0200, Clemens Ladisch wrote:
>     > Azizul Hakim wrote:
>     > > Driver didn't start the DMA: Not sure how to track on this point. Any
>     suggestion?
>     > > Interrupt do not arrive correctly: Is this the hardware issue or ALSA
>     issue?
>     >
>     > These would imply that some your driver, or some code used by your driver,
>     > did not configure the DMA/interrupt correctly.
> 
>     On beaglebone it may also be that the McBSP port clocking is not
>     configured correctly.
> 
>     Liam
> 
> 


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Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Azizul Hakim]

Yes, I tested with kernel 3.8.13 in both ubuntu and beaglebone.

On Mon, Jun 22, 2015 at 2:55 AM, Peter Ujfalusi <peter.ujfalusi@ti.com>
wrote:

> On 06/17/2015 05:53 PM, Azizul Hakim wrote:
> > Okay, its good to learn something new on every day. So how do I configure
> > McBSP port clocking? I'm very new on these things and was unable to find
> any
> > useful link on this point. :(
>
> I don't see anything in the driver [1] which would indicate that the issue
> is
> in any ways specific to BeagleBone (apart from the beagleaudio strings in
> the
> driver). You are not using the McASP, nor the edma-pcm/davinci-pcm.
> What you seams to have is a custom sound card driver for USB. Is there a
> reason why you could not use the already available USB sound card for this?
>
> Are you running exactly the same kernel under ubuntu and debian?
>
> --
> Péter
>
> [1] https://github.com/azizulhakim/beagleusb/blob/master/beagle-audio.c
>
> > On Wed, Jun 17, 2015 at 5:05 AM, Liam Girdwood
> > <liam.r.girdwood@linux.intel.com <mailto:liam.r.girdwood@linux.intel.com>>
> wrote:
> >
> >     + Peter for Beaglebone
> >
> >     On Wed, 2015-06-17 at 10:01 +0200, Clemens Ladisch wrote:
> >     > Azizul Hakim wrote:
> >     > > Driver didn't start the DMA: Not sure how to track on this
> point. Any
> >     suggestion?
> >     > > Interrupt do not arrive correctly: Is this the hardware issue or
> ALSA
> >     issue?
> >     >
> >     > These would imply that some your driver, or some code used by your
> driver,
> >     > did not configure the DMA/interrupt correctly.
> >
> >     On beaglebone it may also be that the McBSP port clocking is not
> >     configured correctly.
> >
> >     Liam
> >
> >
>
>
>
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Re: Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Antonio Ospite]

On Mon, 22 Jun 2015 11:00:42 -0400
Azizul Hakim <azizulfahim2002@gmail.com> wrote:

> Yes, I tested with kernel 3.8.13 in both ubuntu and beaglebone.
>
> On Mon, Jun 22, 2015 at 2:55 AM, Peter Ujfalusi <peter.ujfalusi@ti.com>
> wrote:
[...]
> > Are you running exactly the same kernel under ubuntu and debian?
[...]

Excuse me, Azizul, but in the thread you compare ubuntu and debian and
then here you say "ubuntu and beaglebone", do you mean:

  - Ubuntu on _PC_ and Debian on _beglebone_?

Maybe it's a silly question, but better be sure, because the
distribution should not make a huge difference when using the same
kernel, but the architecture does if it's a memory issue.

And please try to avoid top-posting :)

Ciao,
   Antonio

-- 
Antonio Ospite
http://ao2.it

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?