Hi On 09/13/2014 10:18 AM, Gunter Königsmann wrote: > Dear Mr. Nyman, > > I have finally found out why my scanner isn't working and since it > seems like the cause is might be be a kernel bug I thought I'd better > report it. > I hope you are the right person to send this bug report to. > > Kind regards, > > Gunter. > > [1.] One line summary of the problem: > rounding interval to 128 microframes, ep desc says 255 microframes > [2.] Full description of the problem/report: > When xhci support is enabled my Perfection V10 scanner as well as the > memory sticks from some of my colleagues will appear in lsusb. But I > won't be able to access them. What I do get is a dmesg like: > > [ 582.536845] usb 2-1: new high-speed USB device number 5 using xhci_hcd > [ 582.704435] usb 2-1: New USB device found, idVendor=04b8, > idProduct=0133 > [ 582.704445] usb 2-1: New USB device strings: Mfr=1, Product=2, > SerialNumber=0 > [ 582.704450] usb 2-1: Product: EPSON Scanner > [ 582.704454] usb 2-1: Manufacturer: EPSON > [ 582.704873] usb 2-1: ep 0x81 - rounding interval to 128 > microframes, ep desc says 255 microframes > [ 582.704898] usb 2-1: ep 0x2 - rounding interval to 128 microframes, > ep desc says 255 microframes >
We got reports of other scanners some time ago with the same issue on linux-usb mailling list. And they also report rounding of microframes from 255 to 128. As this is a highspeed device, with interval value of 255 it must be a bulk endpoint, and we should only set the interval for OUT bulk endpoints (NAK rate), but this shows that we also set it for the IN endpoint. I think interval value for bulk in endpoints should be ignored, and setting it should not matter, but we could try not setting it, I'll see if can create a patch, I don't have high hopes for it though I added the linux-usb mailing list to cc -Mathias -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
