On Sun, Sep 21, 2008 at 10:15 AM, George Spelvin <linux@xxxxxxxxxxx> wrote: > "Grant Grundler" <grundler@xxxxxxxxxx> wrote: >> On Sat, Sep 20, 2008 at 8:17 AM, George Spelvin <linux@xxxxxxxxxxx> wrote: >>> I just got a couple of MSI KA92 (AMD 790FX-based) motherboards with >>> 8 GiB of RAM each. I noticed on boot that the SB600 AHCI implementation >>> had a 32-bit DMA limitation, and looking in the archives, it >>> appears that folks from AMD think it doesn't need to be there. >> >> URL? >> Just want to be sure I'm looking at the same thread. > > "About forcing 32bit DMA patch for AMD690G(SB600)" > http://marc.info/?t=120107450600001 It looks like the results from people testing it further never arrived... >From git commit a878539ef994787c447a98c2e3ba0fe3dad984ec ("ahci: work around ATI SB600 h/w quirk"), it looks like the initial idea was to limit each command to a maximum of 255 sectors (but to still allow 64bit DMA), but according to a later commit (4cde32fc4b32e96a99063af3183acdfd54c563f0; "ahci: SB600 workaround is suspect... play it safe for now") this did not solve the lockups. But there are references in the thread above to broken MSI on the SB600 possibly being the cause of the problem, and now that commit 22b5e7a74280deae560c20ee1a9b502b35181327 ("ahci: SB600 ahci can't do MSI, blacklist that capability") has gone in maybe this is why you're able to get 64bit DMA working? (although we do need more hints on how to conclusively test this) Thanks! Mark -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
