[elrepo] el6: stability of cdc-acm module

[Björn Gerhart]

Hello, I'm experiencing an issue on el6 with cdc-acm, which I'm not able to reproduce on demand. Maybe it’s some timing issue hard to localize. When the error occurs, the port seems to get misconfigured and therefore gets unusable. Even a rmmod and new modprobe does not help, although the device gets a fresh ttyACM node. Only the manual disconnect and reconnect of the device’s USB cable helps on the running system.

The latest stable kernel release seems to be 4.2.1. The recent changelogs in cdc-acm.c of this kernel release show some modifications in respect of stability, which hopefully would solve my problem. Therefore I would like to give it a try in a long term test, to see if the error still occurs.
I simply tried to copy the latest drivers/usb/class/cdc-acm.c and cdc-acm.h into the el6 kernel source code and to compile it, but it turns out that include/linux/tty.h and other dependent files has also changed meanwhile. So it’s not just a quick compile, but a more complex backporting process there.

Do you experience similar problems like described above?
Are you interested in (helping) backporting the latest changes, in order to create a new kmod RPM package?
Is it planned to provide the kernel-ml 4.2.1 rpm package? (for testing purpose on my side)

Best - Björn