On Tue, Jun 08, 2010 at 11:25:58AM -0700, Matthew Dharm wrote: > 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? No, it should be in msec units, not HZ. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
