On Tuesday 18 December 2012 08:49:31 Andrew Turner wrote: > Hello, > > Oleksandr and myself have been looking into why when we enable the > write-back cache on the PandaBoard there are kernel panics with USB. We > have tracked it down to an issue appending the ehci_qh_t to the list at > the end of ehci_setup_standard_chain(). > > I have a patch at  that allows me to run sha256 on a 40MB file over > NSF using the built in smsc USB ethernet chip. The problem is I have > had to place a call to DELAY before EHCI_APPEND_QH. This is obviously > not the correct solution. > > Is anyone able to help me narrow down what is missing? It appears to be > a missing cache invalidate or flush somewhere but I haven't been able > to track down what cache function the DELAY is working around. > > Andrew > >  http://fubar.geek.nz/files/freebsd/ehci_4.diff
Hi, Can you dump the DMA tag belonging to the QH via and check wether it is mapped coherent or not. Thes QH- and TD- structures should not be cache mapped. Else cache has not been disabled on those pages. qh->page_cache->tag --HPS _______________________________________________ firstname.lastname@example.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"