From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Wed, 30 Jan 2013 09:31:12 +0100 Subject: [Buildroot] can not open ttyUSB0 In-Reply-To: <5108BD5B.3050001@linkwisetech.com> References: <5108BD5B.3050001@linkwisetech.com> Message-ID: <20130130093112.73034ecd@skate> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Adeel Nafis, On Wed, 30 Jan 2013 11:27:39 +0500, Adeel Nafis wrote: > After attaching a 3G Modem USB I am able to successfully use > 'usb_modeswitch" and get the device to switch with messages indicating > that the device is connected to /dev/ttyUSB0,1,2. However, after this I > can not open the /dev/ttyUSBx any more. If i use gnokii for arm it > prints out some messages indicating that it failed to open the port. > > Gnokii output > GNOKII Version 0.6.26 > Gnokii serial_open: open: No such device <----- the port here is > set to /dev/ttyUSB0 > Couldn't open ATBUS device: No such device > Telephone interface init failed: Command failed. > Quitting. > Cannot unlock device. > Command failed. > > I have tested the thing out with Ubuntu for arm on the same platform and > can verify that it works. Before trying to access the device through /dev, make sure that your kernel has actually detected this device, and that a driver has been bound to it: *) Check your dmesg to see if there is something related to your 3G modem and the creation of ttyUSB0 *) Check /sys/class/tty/ and check if there is a ttyUSB0 symlink. Until there is no ttyUSB0 symlink, it means that the kernel hasn't detected the device, or that a driver is missing for it. *) Once you have /sys/class/tty/, do a cat /dev/class/tty/ttyUSB0/dev and check that the major/minor that you see here match the ones you have used in the static device table (but it seems like 188:0 is correct for ttyUSB0, so your problem is most likely due to the fact that the kernel has not detected the device at all). Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com