PL2303 Driver Bug in 5.13 Kernel

[Bryan Bourn]

Looks like 5.13.0 kernel broke something in the USB-serial PL2303 driver module. I have a Sky-Watcher EQ6-R Pro telescope mount with a PL23D3 USB-serial chip (I think). My MSECORE mini PC running Ubuntu 20.04.3 has been working with this mount for the last couple of years with the 5.11 kernel. Now with the 5.13 kernel, the pl2303 module doesn't recognize the USB-serial device. I revert back to the 5.11 kernel and it works fine again. Here's the snippets from dmesg:

5.13.0-28-generic kernel:
[ 2.894277] usbcore: registered new interface driver usbserial_generic
[ 2.894292] usbserial: USB Serial support registered for generic
[ 2.907539] usbcore: registered new interface driver pl2303
[ 2.907574] usbserial: USB Serial support registered for pl2303
[ 2.907596] pl2303 1-6:1.0: pl2303 converter detected
[ 2.907602] pl2303 1-6:1.0: unknown device type, please report to <email address hidden>

5.11.0-27-generic kernel
[ 3.201216] usbcore: registered new interface driver pl2303
[ 3.201228] usbserial: USB Serial support registered for pl2303
[ 3.201243] pl2303 1-5:1.0: pl2303 converter detected
[ 3.201349] usb 1-5: pl2303 converter now attached to ttyUSB1

[Ubuntu Foundations Team Bug Bot (crichton)]

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[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1960579

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.