On Sun, Mar 26, 2017 at 6:14 PM, Ben Skeggs <skeggsb@xxxxxxxxx> wrote: > On 03/19/2017 06:23 AM, Ilia Mirkin wrote: >> >> The NV4A (aka NV44A) is an oddity in the family. It only comes in AGP >> and PCI varieties, rather than a core PCIE chip with a bridge for >> AGP/PCI as necessary. As a result, it appears that the MMU is also >> non-functional. For AGP cards, the vast majority of the NV4A lineup, >> this worked out since we force AGP cards to use the nv04 mmu. However >> for PCI variants, this did not work. >> >> Switching to the NV04 MMU makes it work like a charm. Thanks to mwk for >> the suggestion. This should be a no-op for NV4A AGP boards, as they were >> using it already. > > This is probably fine for NV4A in that case (more below). > >> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70388 >> Signed-off-by: Ilia Mirkin <imirkin@xxxxxxxxxxxx> >> Cc: stable@xxxxxxxxxxxxxxx >> --- >> >> OK, so I'm not 100% sure about my claims, but I don't have the necessary >> hardware to test it out. Right now, AGP nv41+ boards are getting the nv04 >> mmu, while PCI nv41+ boards are getting the PCIE one. Perhaps this works >> for them, however such boards are rare, and I don't have one. Perhaps all >> PCI boards should be routed to the nv04 mmu, not just the NV4A ones. > > I wonder if it wouldn't be useful to also change the checks in nv41/nv44 > implementations to be "if (device->type != NVKM_DEVICE_PCIE ..." too? So ... mwk and I were talking about it, and we weren't sure. Were there non-NV4A, non-IGP PCI boards? And if so, if it's a PCIE <-> PCI thing that translates the bus transactions, the GPU-side MMU should still be there, no? (Is there anything PCIE-specific going on?) In case you can't tell, I'm well past the edge of my understanding of how all this works... Perhaps you could check if you have such a board, or if they're purely mythical? If such boards do exist, see what happens when you plug it in and boot nouveau with it. My issues with NV4A were immediate - the fifo basically didn't initialize. If the boards are mythical, then we can just change nv44/nv41 to check for != PCIE. Cheers, -ilia _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
