On Tue, Jun 08, 2010 at 01:02:03PM -0300, Thiago A. Corrêa wrote: > Hi, > > A few days ago I created a bug report > (https://bugzilla.kernel.org/show_bug.cgi?id=16094) about a problem > with the CP210x driver in the linux kernel. > As suggested by Greg Kroah-Hartman, I'm forwarding the list the > kernel log messages and lsusb output. > > The problem is that a fopen() to /dev/ttyUSB0 fails most of the > times with older kernels (2.6.26) and all the time with newer kernels > (2.6.33.3). I found that a simple test is stty -F /dev/ttyUSB0. This > fails with "Protocol error". > Opening the port with minicom also triggers the same issue. > > I began to compare the cp210x with the ftdi_so and I found that > they use very different values for the usb_control_msg() call. The > first uses 300 while the later uses 5000. The original driver from > Silabs (available at their website) also uses 300. I changed it to > 5000 (see patch below) and it seems to fix the problem for me. But > since I'm no kernel hacker, I'm not so sure if this is a proper fix or > not. > That parameter is a timeout. Isn't it supposed to be expressed as a multiple of HZ, which is often but not always 100? Matt -- Matthew Dharm Home: mdharm-usb@xxxxxxxxxxxxxxxxxx Maintainer, Linux USB Mass Storage Driver My mother not mind to die for stoppink Windows NT! She is rememberink Stalin! -- Pitr User Friendly, 9/6/1998
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