Re: [hylafax-users] Request For Linux Kernel Help: Was 2.6.26 Breaks USB Modem

[Riccardo Magliocchetti <riccardo.magliocchetti@xxxxxxxxx>]

Frank Peters wrote:
> Last week I reported that the latest Linux kernel 2.6.26  breaks
> faxing with a USB modem.  The problem has been acknowledged (flow
> control is broken) and a possible way to pinpoint the cause is to
> bisect the kernel versions with git.
>
> Unfortunately, I don't have the necessary background to accomplish
> this task and I am requesting that anyone interested who has the skills
> to please contact the linux-usb list at linux-usb at vger dot kernel dot org.

I don't have an usb cdc modem so i cannot do it myself, but i've taken a 
look at git history from gitweb at git.kernel.org of linus' tree. there 
weren't lot of changes [1] to usb cdc acm driver and [2] looks to me the 
better candidate to cause a regression. For reference the timeframe from 
linux 2.6.25 to 2.6.26 is between 16 april and 13 july.

So you can try to download this commit [2] and revert the patch with 'patch 
-R -p1 < file.diff' from 2.6.26 kernel source. Probably you have to fix some 
hunks manually.

HTH,
Riccardo

[1] 
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=history;f=drivers/usb/class/cdc-acm.c;h=c3201affa0b6f99c17ff6d28c71e3cd08adb58c6;hb=bce7f793daec3e65ec5c5705d2457b81fe7b5725
[2] 
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff_plain;h=e4cf3aa8f9cd6ee4d583b5d445b5c152acefcde4


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