On Wed, 26 Jun 2013, Mariusz Grecki wrote: > The problem relates directly to the old one: > > http://thread.gmane.org/gmane.linux.usb.general/20816/focus=20850 > > The problem is, that usually (in fact all the time with one! exception > so far) the card is recognized by operating system as a full-speed (FS) > device not the high-speed (HS) one. This is weird, but once I have seen > it was recognized as high-speed device at my CPU. But that happened once > - I have no idea how and why. My suspicions is that during > initialization there is a kind of races that usually lead to full-speed > configuration. Speed determination is performed in hardware, not in software. You mentioned below that the card was plugged into a hub, not directly into the computer. Therefore the speed was determined by a negotiation between the hub and the card. The CPU was not involved. > The FS operation is not enough since the card performance is limited or > (worse) the card is not possible to use since there are other USB > devices connected (not enough bandwidth). > > One of the possible cause given in the mentioned thread was that the > card requires special initialization. This is not the case in my opinion > since I have seen it was initialized as a HS device with completely > different characteristics (more high precision and high sampling rate > modes of operation). Instead of guessing, you really need to find out if Windows uses any special initialization. > The computer to which the card is connected is uTCA embedded CPU with > high-speed USB hub. It runs Ubuntu 10.04 (Linux mskcpucmtb1 > 2.6.32-45-generic #102-Ubuntu SMP Wed Jan 2 22:38:04 UTC 2013 x86_64 > GNU/Linux). I have checked the same behavior with pure 3.9.2 kernel > compiled by me - for all cases FS device was configured. The only case > when the device was configured as HS device happened once with other > machine (not available at this moment). But it is not related to this > particular machine since I have tried many times on this machine later > and always it was configured as FS device. > > I have read several problem reports concerning these cards at Internet > (most of them seem to be related to FS configuration). > > Certainly I can provide more information (logs, CPU setup etc.). None of that will help. But there is one possibility you should take into account: Maybe the hub or the card isn't getting enough electrical power. > Does anybody have any idea what can be the problem? The card is > recognized as HS device by MS Windows (XP version) without any exceptions... What happens if you run Linux on the Windows machine (for example, boot from a Live CD)? 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
