CRC error with Sony STR-DH550

[zanppa]

Hi.

I got the driver and the userspace application to work and tested the driver with my Sony STR-DH550 amplifier. The amplifier tries to read the "iPod" but I see that the process (the "ipod" userspace program) shows a CRC error:
ERRO[0025.020803] << PACKET error=packet decode: crc mismatch: recv 53 != calc 8c len=0
ERRO[0025.021055] << PACKET error=packet decode: crc mismatch: recv 70 != calc 94 len=0

I uploaded the trace file to https://pastebin.com/TUa5nt4U
In the file, the process runs for a while, then stops to the CRC error. After a while it runs ok for some time and then another CRC error appers. That's when I stopped the trace.

Any ideas what might be wrong?

[oandrew]

Looks like a USB/HID packet is lost. Could be hardware or software bug/problem.

• what is your gadget side hardware?
• logs from dmesg might help

[zanppa]

I use Raspberry PI Zero W with custom kernel 4.14.37+. Are there some specific things you'd need to know?

You can find the relevant part of dmesg log (kern.log) from https://pastebin.com/RTvyqTdt
The log starts when I loaded the first (audio) module. I then let it run so that the CRC error came 3 times, then I stopped the ipod userspace program.

[zanppa]

I tried this again with the latest version of the driver and the "ipod" userspace program, and now there is no CRC errors anymore and the gadget is detected by the amplifier.

However, I cannot get the speaker-test to work, running

speaker-test -D hw:CARD=iPodUSB,DEV=0 -c 2 -r 44100

seems to run for about 10 seconds but no sound is heard. After that, it dies with last messages:

0 - Front Left
Write error: -5,Input/output error
xrun_recovery failed: -5,Input/output error
Transfer failed: Input/output error

Any hints on what might be the issue?

EDIT2: Realized I can attach the trace file instead of using pastebin, here it is:
ipod.trace.log

Also I noticed that using any the amplifier's OSD to navigate the contents (with the default "ipod" userspace app) the amplifier hangs when selecting anything (like artists). I assume this is a limitation of the userspace app?