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. -- 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
