On 11 February 2010 06:54, Gu, Yang <yang.gu(a)intel.com> wrote:
In oFono code, "device4" represents the modem, while
"device1" is the udev_device when calling function add_huawei_em770(modem,
udev_device). When I check if it's ttyUSB2 or not in my code, I think I'm checking
the device1 and its sysname (Showed as KERNEL in device1, but not the one showed in /dev
directory), and in the context of this modem (device4). I do believe there may be some
other ttyUSB2 in the system, for example, we have another em770 modem pluged in. But these
two ttyUSB2 are in different context. I ever tried to change the name showed in /dev
directory by writing some udev rules, but this sysname (KERNEL) seems stable (It's
still ttyUSB2). Is it possible this sysname gets changed under some circumstance expect
the kernel or driver changes? If not, I still think it's safe and convenient to check
this value here.
Honestly I don't know. But the whole /dev path may change between
kernel versions, for example I believe "ttyUSB" was "ttyU" a long
time
ago (I'm not 100% sure). So in my opinion the safe way is to compare
the "bInetrfaceNumber" and "configuration" of the parent devices to
"02" and "Huawei Configuration".
Best regards