I’ve been trying to troubleshoot an issue, but lacking experience working in the kernel, and not being able to find this same issue discussed elsewhere, I could use some help.
Basically, I have a USB communication class device interface with my BBB that only works once between booting. I’ll power up, send a character command to the device, and get the expected response back … but if I send the same command again, fgets never returns a non-null string. If I reboot the BBB, I can send the command and get the expected response back, but, again, only once.
Other USB issues I’ve seen discuss power, and my device is bus-powered, but I don’t think it’s a power issue, as I found the following in dmesg, which doesn’t seem to relate to power (this message appears after the first time sending a command to the device, and every time thereafter):
WARNING: at drivers/usb/musb/musb_host.c:125 musb_h_tx_flush_fifo+0x35/0x5c()
Any ideas on how to troubleshoot this? Again, I have no experience working in the kernel, so I’m at a loss. My only idea was to examine the code throwing the warning, but, mysteriously, I searched the entire file system (find / musb_host.c) and couldn’t locate musb_host.c … how could that file be throwing the warning if it seemingly doesn’t exist on my file system?
This is a company project and we’re willing to pay for a solution at this point.