Please cc me as I'm not subscribed ... I have some issues with the Pyramid USB LCD display which is equipped with an ftdi_chip. The relevant dmesg output: usb 5-2: new full speed USB device using ohci_hcd and address 3 usb 5-2: New USB device found, idVendor=0403, idProduct=e6c8 usb 5-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0 usb 5-2: Product: KBS USB LCD Display usb 5-2: Manufacturer: KBS usbcore: registered new interface driver usbserial USB Serial support registered for generic usbcore: registered new interface driver usbserial_generic usbserial: USB Serial Driver core USB Serial support registered for FTDI USB Serial Device ftdi_sio 5-2:1.0: FTDI USB Serial Device converter detected usb 5-2: Detected FT232BM usb 5-2: Number of endpoints 2 usb 5-2: Endpoint 1 MaxPacketSize 64 usb 5-2: Endpoint 2 MaxPacketSize 64 usb 5-2: Setting MaxPacketSize 64 usb 5-2: FTDI USB Serial Device converter now attached to ttyUSB0 usbcore: registered new interface driver ftdi_sio ftdi_sio: v1.6.0:USB FTDI Serial Converters Driver With recent kernels the display text ouput is very slow and it seems to be some kind of luck if the server screen of lcdproc comes up. Even recognition of keypress is delayed. The workaround I've found is: - make sure CONFIG_HZ is <= 250 - disable highres timers While using highres=off on kernel command line is quite easy, it's very problematic to force users to build a new kernel if CONFIG_HZ is set to 1000. And to me it seems that more and more distributions step forward using CONFIG_HZ=1000. I think the problem is somehow related to delayed interrupt handling of the display driver. But I don't know where to look at. I think ftdi_sio.c and usb-serial.c are involved. Any help is appreciated. Best regards Joerg -- 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
