2010/8/15 Dennis Nezic <dennisn@xxxxxxxxxxxxxxxxxx>: > On Sun, 15 Aug 2010 12:10:30 +0800, Ming Lei wrote: >> 2010/8/15 Dennis Nezic >> <dennisn@xxxxxxxxxxxxxxxxxx>: >> > It looks like that patch made things more consistently *worse* :b -- >> > which I guess is some kind of progress? :b In the "detected XactErr" >> > messages, absolutely nothing is transferred? (ie. the ratios are >> > always 0/some-low-number ... whereas before there was a lot more >> > variety like 3584/4096, etc.). >> >> Sorry, I don't have any ideas about it. >> >> 'detected XactErr' means below (from ehci 1.0 pg. 54) >> >> Transaction Error (XactErr). Set to a one by the Host Controller >> during status update in the case where the host did not receive a >> valid response from the device (Timeout, CRC, Bad PID, etc.). Refer >> to Section 4.15.1.1 for summary of the conditions that affect this >> bit. If the host controller sets this bit to a one, then >> it remains a one for the duration of the transfer. >> >> Generally speaking, it means a hardware level issue. >> >> The patch only adds 125us delay before transmitting data with device >> or receiving CSW. I don't know why it make more worse than before, >> seems it should not put any side effect on normal device. > > Well, it does :P -- and IMHO it's an important clue. If adding a 120us > delay degrades performance* considerably, perhaps (pure handwaving) it > is some kind of timing or interrupt problem? > > * (Before the patch, it made a little progress -- it was able to detect > the capacity of the memory card in it -- with the patch it gets almost > nowhere... although in both cases, the first 3 or 4 > usb_stor_bulk_transfer's consistently work perfectly -- the problematic > transfers only seem to happen a bit after the scsi multiple lun > detection thingy finishes.) > > >> BTW: You try the card reader on Windows OK, is the windows installed >> on the same machine with linux? Are you sure for the same machine and >> same card reader(includes cable), only windows can work and linux does >> not work? > > I tested it with another MSWindows machine, same cable. As I said, your issue is very possible a hardware related, so recommend to do the compared(windows vs. linux) tests on same machine for ruling out hardware problem. thanks, -- Lei Ming -- 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
