Linux: am33xx, musb, cppi41 packet loss ?

user5131608

Tool/software: Linux

On Am33xx I am using a bluetooth adapter over musb host using cppi41.

I'm doing some Bluetooth Audio using a USB adapter. It using RFCOMM and SCO (the former uses bulk transfer the latter uses isochronous transfers), i am missing a packet in a bulk transfer after the isochronous transfer stopped.

This seems to happens during or even after isochronous packet was received, i can receive still data from the bluetooth adapter, but the first send does not seem to happen, even though I am seeing the tx complete. I mean, I am expecting a response from the adapter that I do not see. So I guess that the adapter did not receive the message. I also tried different adapters to rule out.

I have a very simple code that can reproduce the issue on 1/3 rate.

I noticed that If I don't establish the audio connection, there is no packet loss.

The kernel on this device is 4.9 kernel with lkml.org/.../1167

Is this a known issue?

Any suggestion would be welcome, thanks,

over 6 years ago

0 Pavel Botev over 6 years ago

TI__Guru**** 170625 points

Hi user5131608,

Do you use AM335x TI board (EVM, SK, BBB) or it is custom board?

Do you use AM335x TI PSDK v4?

software-dl.ti.com/.../index_FDS.html

Regards,
Pavel

0 Dwarakesh Radhakrishnan over 6 years ago

Guru 13620 points

Hi,

1. Which software package are you using, is it from TI ?
2. Have you made sure musb patches mostly like ZLPs as mentioned in the link : processors.wiki.ti.com/.../Sitara_Linux_MUSB_Issues are in place in your code ?
3. Will you be able to catch hold of an USB analyzer and check if actually the data is going out ? What is the expected data size to be sent out ?
4. Please do check arago-project.org/.../
arago-project.org/.../
arago-project.org/.../

are also in place.

0 user5131608 over 6 years ago in reply to Pavel Botev

Prodigy 80 points

Hi Pavel,

Thanks for your response.

We use a custom board derived from the beagle bone black.

Regarding the kernel, i don't think it is the TI SDK, we have 4.9.30 with many patches.

Regards,
Fred

0 user5131608 over 6 years ago in reply to Dwarakesh Radhakrishnan

Prodigy 80 points

Hi Dwarakesh,

1) I do not think we use TI package.
3) Unfortunately, I don't have a USB sniffer at the moment. I wonder if a beagle bone as a proxy could be reliable for that ?
2 - 4) I'll double check each
Thanks for your feedback.

Fred

0 Dwarakesh Radhakrishnan over 6 years ago in reply to user5131608

Guru 13620 points

Hi Fred,

You can download the TI SDK and give a quick try by using its kernel. Beaglebone as a proxy would be tough to have, but you can give a try if it is possible. How do you want it to be proxy?

0 user5131608 over 6 years ago in reply to Dwarakesh Radhakrishnan

Prodigy 80 points

Hi Pavel and Dwarakesh,

I have installed the SDK with a beaglebone black and the issue reproduced. The bbb kernel is 4.4.9-ti-r25.

About our kernel, I was told it was "very similar" to yours but not equal.

Best regards,

Fred

0 user5131608 over 6 years ago in reply to user5131608

Prodigy 80 points

I have more informations that could be useful:

The adapter I used (let's call it a0) integrates a HUB. I realized that the issue did not occur at all using an adapter that did not use integrated HUB (a1).

If the adapter a1 is plugged on a external HUB, the issue starts occuring.

I tried to lower to full-speed rather than high-speed, and it didn't help.

0 Pavel Botev over 6 years ago in reply to user5131608

TI__Guru**** 170625 points

Fred,

user5131608 said:
I have installed the SDK with a beaglebone black and the issue reproduced. The bbb kernel is 4.4.9-ti-r25.

Which SDK you have installed? Have you tried with AM335x PSDK 4.01 (kernel 4.9.41)?

software-dl.ti.com/.../index_FDS.html

0 user5131608 over 6 years ago in reply to Pavel Botev

Prodigy 80 points

Pavel,

This is the SDK as it is installed on my computer: ti-processor-sdk-linux-am335x-evm-04.01.00.06
I used create-sdcard.sh to create sdcard, then apt update/upgrade.

It doesn't seem to contain the kernel you mention, how can I test it?

Regards,

Fred

0 Pavel Botev over 6 years ago in reply to user5131608

TI__Guru**** 170625 points

Fred,

Can you provide full console boot up log?

ti-processor-sdk-linux-am335x-evm-04.01.00.06-Linux-x86-Install.bin

ti-processor-sdk-linux-am335x-evm-04.01.00.06/board-support/linux-4.9.41+gitAUTOINC+e3a80a1c5c-ge3a80a1c5c

Regards,
Pavel

0 user5131608 over 6 years ago in reply to Pavel Botev

Prodigy 80 points

Ha Pavel,

Thanks, I just realized the device was in fact booting from the emmc !

let me retry

Regards,

Fred

0 user5131608 over 6 years ago in reply to user5131608

Prodigy 80 points

Just a quick update:

It now booted the right kernel, but the kernel (4.9.41) did not contain the btusb module.

I have rebuilt it, it is loading, but now python3 is missing bluetooth support, and this is the language I used to implement my test. I am getting python to build now.

Regards,

Frédéric

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Linux: am33xx, musb, cppi41 packet loss ?