On Fri, 13 Jul 2012, Sami Farin wrote: > > The card reader has a couple of bugs in its firmware. It's odd that > > the errors occur only when running at SuperSpeed. You'd think the > > firmware would behave the same way regardless of the speed. > > > > Anyway, you can work around one of the bugs by specifying a quirk > > parameter for usb-storage: > > > > modprobe usb-storage quirks=8564:4000:m > > > > To fix the other bug will require adding a blacklist entry for the card > > reader. First let's see if the quirk alone will get it working. > > > > Alan Stern > > Unfortunately it still does not work. > I first re-ran mkfs.vfat when connected to usb2 port and then tried to write 512 MB > with usb3.. > > usbmon with quirk enabled > https://docs.google.com/file/d/0B_EMXtsx7o56bEtobmJwYi1TaWc/edit That's really weird. Your log confirms that the quirk was recognized: > [81577.678735] usb-storage 4-2:1.0: usb_probe_interface > [81577.678739] usb-storage 4-2:1.0: usb_probe_interface - got id > [81577.678767] usb-storage 4-2:1.0: Quirks match for vid 8564 pid 4000: 400 And yet the usbmon log shows that the quirk didn't take effect. That's why the problem occurred again. After the device is plugged in, what shows up in the /sys/block/sdg/queue/max_hw_sectors_kb file? Without the quirk it should contain 120; with the quirk it should contain 32. The effect of the quirk is to reduce the maximum size allowed in a single data transfer from 120 KB to 32 KB. The usbmon trace shows that your card reader got an error when it was asked to write a 120-KB buffer. Reducing the transfer buffer size should eliminate the errors -- but that the latest usbmon trace still shows a 120-KB transfer. I tried doing an equivalent test on my system (using reads, not writes) and it worked fine. I got 32-KB transfers instead of 120-KB transfers. I have no idea why it didn't work on your system. Maybe you should do some tests with reads instead of writes. A simple test would be: dd if=/dev/sdg of=/dev/null bs=1M count=1 Let's compare the usbmon traces for that command with and without the quirk present. 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
