On Sat, Jul 14, 2012 at 12:39:49 -0400, Alan Stern wrote: > On Sat, 14 Jul 2012, Sami Farin wrote: ... > > it worked with 1M with and without quirks, but with 300M it failed without > > quirks, OK with quirks (36 MB/s, though it was advertized 85 MB/s). > > The usbmon logs show just what they should: 32-KB transfers with the > quirk and 120-KB transfers without it (actually more like an > alternating pattern of 120 KB followed by 8 KB -- I don't know why; it > might be an artifact of readahead). > > Well, the quirk is definitely going to slow things down a little, > just how much I'm not sure. But that's better than losing data. :-) > As for why the non-quirk 1-MB transfer worked... It's hard to say. > The bug might affect reads differently from writes. > > I'm still puzzled about the previous test, though. Is it possible that > you posted a usbmon trace that was taken without the quirk? That 1 MB test? 0.1% possible ;() > Tell you what: Try capturing a single trace including both a 1-MB read > and your failing write test (and with the quirk present, of course). > If something strange is going on, that should show it. OK, I read 1 MB with dd, then mount it, then cp /dev/urandom . , then umount. $ cp /dev/urandom . cp: writing `./urandom': Input/output error cp: failed to extend `./urandom': Input/output error after mounting again, df shows 8568 KB used, but directory empty. quirktest-dmesg.txt https://docs.google.com/file/d/0B_EMXtsx7o56U20tWVVTSHFNRmM/edit quirktest-usbmon.txt https://docs.google.com/file/d/0B_EMXtsx7o56b1YxQVdkcFRxUm8/edit > Alan Stern > -- Do what you love because life is too short for anything else. -- 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
