On Sat, 28 Sep 2013, Markus Rechberger wrote: > >> My next step would be to eliminate the kmallocs/kfrees for the single > >> urbs (just by allocating the urbs with the same mechanism and passing > >> the returned pointer to SUBMIT_URB). > > > > The time spent allocating and freeing URBs is probably pretty small. > > > > pre-allocating should at least solve those issues: > http://support.sundtek.com/index.php/topic,1097.msg7780.html#msg7780 As far as I can tell, that bug report isn't related to URB allocation. It looks like the failure occurred when allocating memory for the transfer buffer, not when allocating memory for the URB. > but now when looking closer SG support can disable the support for > shared memory support for bulk transfers. I don't know what you're talking about. What has shared memory got to do with SG or anything else we are discussing? > It should be possible to turn off SG Support in favor of > pre-allocating the buffers (or preallocate the buffers for SG). Only if the buffer can be allocated as a single contiguous region of memory, in which case SG wouldn't be needed anyway. > This problem happened several times on Sheevaplug ARM systems from Marvell. I don't see what difference the platform or architecture would make. 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
