Hi, thanks for testing this out, from the attachment it looks like your pl2303 does not work with the new device detection algorithm in 5.13 kernel:
https://kernel.ubuntu.com/git/ubuntu/ubuntu-impish.git/tree/drivers/usb/serial/pl2303.c#n421 Which can only handle devices with bcdUSB 1.10 and 2.00 However yours is 1.01: Bus 001 Device 004: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.01 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x067b Prolific Technology, Inc. idProduct 0x2303 PL2303 Serial Port bcdDevice 3.00 I would suggest you to give the latest mainline kernel [1] a try to see if this issue exist with the latest kernel, you will find instructions here [2]. If the issue still exist, please report this issue to linux- u...@vger.kernel.org, indicating the kernel version and attach the lsusb -v output for this device. Thanks! [1] https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.18-rc5/ [2] https://wiki.ubuntu.com/Kernel/MainlineBuilds#How_do_I_install_an_upstream_kernel.3F ** Changed in: linux-signed-hwe-5.13 (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1967493 Title: pl2303 serial adapter not recognized To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-5.13/+bug/1967493/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
