Marek Floriańczyk wrote: > Well I thought about USB because of two reasons: > 1. I need Ethernet port on that Linux box to be used by my server and > it needs to be configured accordingly to home network. It would be > troublesome to use that. > 2. USB is available on most of the computers, and usually more than one. Sure, these are the benefits of USB. > > You are wrong. USB makes a quite significant distinction between host > > and device. It is simply not possible to talk to a host as if you > > were talking to a device. > > I know that it does, but this usb bridge cable has some chip, from > what I understand it presents host as an usb device. This sentence makes no sense, because that is impossible, because hosts and a devices are so very different. I recommend reading chapter 5 and/or chapter 8 of the USB 2.0 spec at http://www.usb.org/developers/docs/usb_20_101111.zip to learn more about the differences. Those two chapters give a great overview. > > I would either choose TCP/IP (most likely over SSH) or indeed > > USB, but if USB then I would make very sure that the embedded > > Linux device *is* a USB device. > > > > http://www.raspberrypi.org/phpBB3/viewtopic.php?t=8089&p=97007 > > > > Explains that even if the software part would work, the rpi USB port > > is actually permanently wired to an ethernet chip. You lose. > > This I didn't know. It is important. > So far I was using small computers based on Vortex86 chipset, they are > a bit more expensive that raspberry but I had no problems handling usb > devices. I think you misunderstand. I am saying that if you want to use USB for administration then you should make sure that your embedded Linux system is a USB device. That is not possible on the raspberry pi because the USB port which might work in device mode is hardwired to a USB-ethernet chip, instead of a connector. So there is no way to connect to that port. I'm sure that the rpi can use USB devices just fine, I am talking about having the board *be* a USB device. > Maybe I will have to stay with it, or I can try OLINUXINO or > ODROID-X, it seems there are plenty of them. And all I need > is good configuration tool based on USB connection ;) I think you need to look for hardware that fits your requirements. If you want to use USB for configuration (which has advantages) then make sure that your hardawre can *be* a USB device. In Linux this is implemented using the so-called gadget subsystem, which provides an API for your application doing the actual configuration. On the other side of the USB cable you could then use libusb. Your embedded Linux would have a device (B, mini-B, micro-B) connector, and the field technician or integrator would not need a special cable, but could use any USB cable. As you write there are plenty of nice modules for embedded Linux, choose one of them which works with the gadget code. My favorites at the moment are the ultra-low-cost Carambola (8devices.com) and Aria G25 (acmesystems.it) modules. The Aria G25 has a huge patch stack on top of 2.6.39, but maybe most of that is upstream already. You'll need to make a PCB to use either of them. //Peter -- 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
