!!OBSOLETE!! Note, somone finally had the patience/pigheadedness to break down the lkml enough to actuallly allow a bugfix to this driver, and parity/flowcontrol/wordsize are now all properly supported since about 4.9/4.10, with a bunch more little fixes and cleanups around the 4.10/4.11. You shouldn't need any of this work anymore, nor should you need you need any other drivers for these parts. ~~~~~ original notes below ~~~~~~ notes on adding parity control support to ch341.c, the linux driver for, as BSD calls it, "the worst usb serial chip in the world" it actually works just fine in windows, and in linux with no-parity, at least for the basic usages I have for it, but yeah, it's ugly datasheet world :) http://wch-ic.com/product/usb/ch341.asp Now to just actually edit the kernel module... Enabling debug from the kernel module: sudo su -c 'echo "file ch341.c +p" > /sys/kernel/debug/dynamic_debug/control' or sudo su -c 'echo "module ch341 +p" > /sys/kernel/debug/dynamic_debug/control' Building it (from a linux tree checkout matching your running kernel on fedora...) make -C /lib/modules/`uname -r`/build M=`pwd`/drivers/usb/serial modules (First time, to get that running kernel... notes to self... make mrproper cp /boot/config-xxxx .config make oldconfig make make modules sudo make modules_install sudo make install ~reboot here~ I have the YSUMA01-341A, plus what ever's inside the 485 dongle YSUMA01-341A http://item.taobao.com/item.htm?id=14541759710 YS-CH341T http://item.taobao.com/item.htm?id=16318219421 YS-CH340T http://item.taobao.com/item.htm?id=17164157198 HL-340 http://item.taobao.com/item.htm?id=17786652096 ~ TO GET VirtualBox working again ... yum install VirtualBox-kmodsrc cd "somewhere" && tar -xf /usr/share/VirtualBox-kmod-4.3.18/VirtualBox-kmod-4.3.18.tar.xz cd vboxdrv && make && sudo make install cd vboxnetflt && make && sudo make install cd vboxnetadp && make && sudo make install sudo systemctl restart systemd-modules-load.service