On Thu, 17 May 2012, Anil Nair wrote: > I observed the dmesg and lsusb log of the cando touchscreen of an Acer > 1825PTZ, it seems that the Cando touchscreen is detected by and > attached to the UHCI controller. I also observed the screen shots by > Gerhard, the cando touchscreen is a full speed device and in windows > it is able to detect it, the Intel C200 chipset supports full > speed,high speed and low speed device; the EHCI driver in Linux wasn't > successfully able to enumerate it. "Enumerate" is the wrong word. The EHCI driver doesn't enumerate anything; the USB core does. Besides, what happened was not a failure of enumeration. The device could be not enumerated because it wasn't detected, and it wasn't detected because it was electrically disconnected from the USB bus. > The dmesg and lsusb list is provided in the link below, > > "https://launchpadlibrarian.net/95270794/BootDmesg.txt"; > "https://launchpadlibrarian.net/95270802/Lsusb.txt"; > > Alan sir, isn't it a possibility that the Cando touchscreen was not > detected by the Linux kernel as a full speed device??? UHCI controller > isn't present in the laptop used by gerhard so i am guessing that > maybe the possibility. No. If your guess was right then no full/low-speed device would work on that laptop, whereas obviously they do. For example, the mouse wheel was detected normally. The Windows screenshot showed that the touchscreen was plugged into a hub, and the port status data from that hub under Linux showed the port was not getting a connect signal (no D+ pullup). Alan Stern -- 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
