On 2024-09-24 16:02, Alex Deucher wrote: > On Fri, Sep 20, 2024 at 11:36 AM Jocelyn Falempe <jfalempe@xxxxxxxxxx> wrote: >> On 17/09/2024 15:21, Alex Deucher wrote: >>> On Mon, Aug 12, 2024 at 2:10 AM Lu Yao <yaolu@xxxxxxxxxx> wrote: >>>> >>>> Add support for the drm_panic module, which displays a pretty user >>>> friendly message on the screen when a Linux kernel panic occurs. >>>> >>>> Signed-off-by: Lu Yao <yaolu@xxxxxxxxxx> >>> >>> Patch looks good to me. Any chance you want to convert the other >>> non-DC dce files (dce_v8_0.c, dce_v10_0.c, dce_v11_0.c) while you are >>> at it? >> >> I've made a similar patch in amdgpu_dm_plane.c, and it works on a Radeon >> pro w6400. >> But it only works when I'm in a VT terminal (so the framebuffer is >> linear and CPU accessible). >> When under Gnome/Wayland, the flag AMDGPU_GEM_CREATE_NO_CPU_ACCESS is >> set, so that means I can't vmap it ? > > It just means that the application does not need CPU access. Whether > or not the CPU can access the buffer or not depends on the size of the > PCI BAR. E.g., if the driver or bios has resized the PCI BAR, then > the CPU can access the entire BAR, but if not you are generally > limited to the first 256M of framebuffer. FWIW, it's also possible to access all of VRAM via MMIO indirect registers. That'll be slower than a direct CPU map, it might be acceptable for drm_panic though, at least as a fallback. -- Earthling Michel Dänzer \ GNOME / Xwayland / Mesa developer https://redhat.com \ Libre software enthusiast
