On Mon, Sep 13, 2010 at 9:53 PM, Axel C. Voigt <avau@xxxxxx> wrote: > Hello list, > > I am let alone with creating a linux process or kernel module that creates a > virtual tty interface on one side and connects directly to the > usbserial/ttyACM module (as if it were a usb serial device such as a modem) > on the other end to be able to test the serial performance of a linux host. > > When achieved, I am planning to start a pppd on both sides to create a > tcp-over-serial connection to transfer data such as an ftp up/download as if > I were connected to the internet with a UMTS mobile phone or UMTS usb stick. > This could then be evolved to have multiple "virtual" UMTS sticks connected > to one linux host to generate load at the linux usb serial layer and is > necessary since I want to be able to ensure that the new speed classes of > serial devices such as HSDPA usb sticks (3.6 or 7.2MBit/s) or even DC-HSPA > (> 50MBit/s) will work flawlessly even when you connect multiple sticks to > one host. > > In the real world this setup will be difficult/impossible as one will rarely > be able to find a mobile cell that supports >7,2MBit HSDPA (at least in my > nearby area :-) as well as the data rate will significantly drop when you > have more than one mobile in a mobile network cell! > > Could one give me a hint, how to create a test environment to artificially > test such a scenario? Could one be of any help whether I can simulate a usb > device in software? > (Resending, as I accidentally knocked off the list last time around) How about using g_serial with dummy_hcd? Maybe you can use the n_ports parameter to add more interfaces. (dummy_hcd gives you a virtual host and device controller pair, so you can play with gadget drivers without needing actual gadget controller hardware. g_serial can behave like a CDC ACM device). It won't be the same as having multiple different modems connected at one time, but you will be able to have multiple serial port sessions running. - Anand -- 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
