On Tue, 17 Sep 2019 at 00:36, Thierry Reding <thierry.reding@xxxxxxxxx> wrote: > > From: Thierry Reding <treding@xxxxxxxxxx> > > Hi Ben, > > I messed up the ordering of patches in my tree a bit, so these two fixes > got separated from the others. I don't consider these particularily > urgent because the crash that the first one fixes only happens on gp10b > which we don't enable by default yet and the second patch fixes a crash > that only happens on module unload (or driver unbind, more accurately), > which isn't a terribly common thing to do. > > I'll be sending out fixes shortly to make the GP10B work more properly > on a wider range of Jetson TX2 devices and enable it by default. > > One thing to mention is that I'm not exactly sure if the first patch is > the right thing to do. I haven't seen any issues after that change, but > I'm also not exactly sure I understand what BAR2 is used for, so I don't > know if I would've even covered those code paths (other than the one > causing the crash at probe time) in my tests. BAR2 on dGPUs is used to map kernel-level GPU objects in VRAM so they can be accessed by the driver. It's pretty much a smaller version of BAR1, but intended for a different purpose. On dGPUs, there's a couple of places (fault buffer address, and fault method buffer on volta) where the GPU wants PRI regs to be poked with an offset within BAR2 rather than an aperture+offset combination. I'm not 100% sure what Tegra parts do here, but presumably if it's working for you, they're happy to just accept a system memory address instead. I guess this would be the right thing to do here in that situation. The more obvious (from a "reading the code" POV) thing to do would be to write Tegra-specific versions of the functions that use nvkm_memory_bar2() to perform this mapping, and use nvkm_memory_addr() instead but I'm not sure if we need/want to go to that effort. It's conceivable it could be required at some point. Ben. > > It'd be great to get Lyude's feedback on the second patch, since that > call to pci_disable_device() was rather oddly placed and I'm not sure if > that was essential for things to work or whether the slightly different > point in time where it's called after this patch is also okay. It looks > to me like it should work fine, but I don't currently have a way to test > this on desktop GPUs. > > Thierry > > Thierry Reding (2): > drm/nouveau: tegra: Fix NULL pointer dereference > drm/nouveau: tegra: Do not try to disable PCI device > > drivers/gpu/drm/nouveau/nouveau_drm.c | 3 +- > .../drm/nouveau/nvkm/subdev/instmem/gk20a.c | 30 +++++++++++++++++++ > 2 files changed, 31 insertions(+), 2 deletions(-) > > -- > 2.23.0 > > _______________________________________________ > Nouveau mailing list > Nouveau@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/nouveau _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
