On Thursday 13 November 2008 21:02, John Baldwin wrote: > On Wednesday 12 November 2008 12:23:14 pm Marc Lörner wrote: > > Hello, > > I just stepped over a problem with my IDE disk running in DMA-mode > > and having more than 4GB of RAM. > > It seems that the whole way down GEOM, ata-disk, ata-dma never is checked > > whether physical address of buffer is less than 4GB an so fits in 32bits. > > => when PRD is set the address is rigorously truncated to fit into 32bit, > > with buffer < 4GB all is quite fine. > > bus_dmamap_load() in ata-dma.c should result in bounce pages being > allocated and having the data copied to pages below 4GB and having those > addresses passed to the callback and stored in the PRD.
Thanks for pointing this out! So it seems that bounce-pages are counted with helper-function run_filter. But this function does never return 1 with dma-pages not lying in range (e.g. paddr > 4GB) but being aligned. Did nobody else have problems on 64bit ide-dma, or is it already working, but I didn't grasp functionality, yet? For now, I came around this by adding a flag in "/sys/bus_dma.h" and setting this flag on tag-creation. So I now can check in run_filter whether I'm doing an ide-dma, relying on this and on check whether I got paddr > 4GB, I then can tell bus_dmamap_load to use bounce-pages. Any thoughts or comments? Regards, Marc Loerner _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
