On 7.3.2023 15.21, Brian Morrison wrote:
Hello Mathias (sorry you're getting this twice). Re-send after linux-usb list rejection (too big). Hans de Goede replied to my Fedora kernel bug here: https://bugzilla.redhat.com/show_bug.cgi?id=2175534 suggesting that I contact you about it and Cc: the linux-usb list. Starting with kernel-6.2.2-300 on Fedora x86_64 (the first 6.2 kernel on Fedora 37) I am seeing problems with USB devices on a Renesas ROM-based USB PCI card which works normally with kernel-6.1.15-200 and earlier 6.x kernels, essentially the USB 2.0 device tree on this card's bus is not being enumerated with the result that my /dev/ttyUSB* devices are no longer present (these are Silicon Labs CP210x UARTS with TI PCM290x devices behind them). I have attached the lsusb -t output for the working and broken cases, I don't know where the problem lies but I suspect it's not udev because the configuration is unchanged, it seems to be in the kernel usb code. There are further attachments in the bug referred to above, I don't know if they help but you can look there if the lsusb output is insufficient, I can point out that lsmod does show the cp210x module is loaded which may provide a clue about where things are failing. Thanks for reading this, I look forward to hearing your suggestions.
Looks like that those devices initially enumerated fine, but suddenly disconnect about 19 seconds after boot. [ 19.155556] usb 2-1.1: USB disconnect, device number 4 [ 19.155685] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0 [ 19.159290] usb 2-1.4: USB disconnect, device number 6 [ 19.242344] usb 2-1.4: 3:0: failed to get current value for ch 0 (-22) [ 20.100761] usb 2-4.1: USB disconnect, device number 8 [ 20.100894] cp210x ttyUSB1: cp210x converter now disconnected from ttyUSB1 [ 20.100999] cp210x 2-4.1:1.0: device disconnected [ 20.107188] usb 2-4.2: USB disconnect, device number 9 [ 20.107253] cp210x ttyUSB2: cp210x converter now disconnected from ttyUSB2 [ 20.107284] cp210x 2-4.2:1.0: device disconnected [ 20.111938] usb 2-4.4: USB disconnect, device number 10 [ 20.181363] usb 2-4.4: 3:0: failed to get current value for ch 0 (-22) Interestingly those are all the devices behind external hubs. Bisecting this to find the offending commit would be best, but a dmesg with xhci and usb core dynamic debug enabled could also show why those devices disconnect. Adding "usbcore.dyndbg=+p xhci_hcd.dyndbg=+p" to your kernel cmdline should do this. Thanks Mathias
