Hi I've been designing a USB device (P18F2455) to communicate with PC(running Linux OS), when the USB peripheral clock speed is 48MHZ and CPU works at 16MHZ, the device works fine, and the Enumeration process is very fast.
But, if the CPU clock speed is changed to 4MHZ and the USB peripheral clock speed remains the same, the initialization fails most times(and it succeeds sometimes, but not offten). Oddly enough, when I connect the device to Windows 2000, it works even when the CPU clock speed is set to 1MHZ(and runs pretty well at 4MHZ)!! My manager wishes it to work at 4MHZ, but I don't even get the idea which part the fault lies in, the device part or the Linux usb driver. My linux kernel is 2.4.8-20, but I've tried 2.6.11.11 and it works no better. I have tried all host controller interfaces: ohci, ehci and uhci, all of them works the same, except the output messages differ: For EHCI, the dmesg output is: usbdevfs: USBDEVFS_CONTROL failed dev 2 rqt 128 rq 6 len 256 ret -110 usb_control/bulk_msg: timeout usbdevfs: USBDEVFS_CONTROL failed dev 2 rqt 128 rq 6 len 256 ret -110 usb.c: USB disconnect on device 00:10.2-1 address 2 usb_control/bulk_msg: timeout usb.c: USB device not accepting new address=3 (error=-110) hub.c: new USB device 00:10.2-1, assigned address 4 usb_control/bulk_msg: timeout For UHCI, the dmesg is: usb-uhci.c: v1.275:USB Universal Host Controller Interface driver hub.c: new USB device 00:04.2-2, assigned address 2 usb-uhci.c: interrupt, status 2, frame# 655 usb_control/bulk_msg: timeout usb_control/bulk_msg: timeout usb_control/bulk_msg: timeout usb_control/bulk_msg: timeout usb.c: USB device not responding, giving up (error=-110) hub.c: new USB device 00:04.2-2, assigned address 3 usb_control/bulk_msg: timeout usb.c: USB device not accepting new address=3 (error=-110) And for OHCI: hub.c: port 2, portstatus 103, change 10, 12 Mb/s hub.c: new USB device 00:02.2-2, assigned address 5 usb.c: unable to get device descriptor (error=-75) hub.c: port 3, portstatus 100, change 0, 12 Mb/s Can anyone help me out, THANKS! ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
