Description of problem:
my self-tinkered chorded keyboard does not deliver key press/release messages with 2.6.40-4.fc15, although it works fine with 18.104.22.168-35.fc15.
on another box (atom N270 (i686)) i have the same problem with another ACM device (self-tinkered) and 2 USB DVB-T TV sticks (vendor: Hauppauge).
Version-Release number of selected component (if applicable):
Steps to Reproduce:
2. start a program that reads from /dev/ttyACM0
open works as before, but nothing is read.
there should be some incoming data.
i found it remarkable, that it fails on 2 boxes, 2 architectures and 2 USB devices.
with 22.214.171.124-0 i still have those problems...
on i686 it crashes after a few minutes (no ethernet access... it is head-less, so that i cant c any special error messages...)...
126.96.36.199-5.fc15.x86_64 still doesnt like my USB device... -arne
188.8.131.52-0.fc15.x86_64 still doesnt treat my ttyACM devices as before...
i had a closer look at it, and now it seems, that it holds back a byte in some buffer, so that a read fails... when a write a further byte, the following read delivers the byte that i expected before...
i think that is a bug in the ACM or USB buffer handling, because: there is no guarantee that there is an infinitely long data stream coming from a serial port...
You should probably email upstream about this. We don't have the hardware to recreate issues and thus far you're the only person reporting a problem.
at linux-kernel mailing list they suggested that the fedora-patches might have caused the trouble...
i could falsify that theory (i used the fc15 kernel SRPM for 184.108.40.206-0 and hacked the SPECS file so that it would be a vanilla kernel (kernel-vanilla-220.127.116.11-0.local.fc15.x86_64.rpm))...
furthermore i gave them some usbmon traces some days ago, but nobody replied yet (maybe they r angry, because i forgot the subject line once...)...
a communication that works with both kernels (it is just about 1msec long):
a communication that works with the 18.104.22.168 kernel but not the 2.6.40 kernel (it has a 50msec pause in the middle, where no USB stuff can be done... my self-tinkered-usb-device talks to some other device in that time, which takes its full concentration... but it is still a bug, that 1 byte hangs in some buffer, i think...):
yesterday i made my self tinkered USB device more USB compliant...
since then the current 2.6.41 kernel works fine...
the TV sticks work fine again, 2... :-)