On 08/31/2018 05:27 PM, Emil Velikov wrote: > On 31 August 2018 at 15:38, Michel Dänzer <michel at daenzer.net> wrote: >> [ Adding the amd-gfx list ] >> >> On 2018-08-31 3:05 p.m., Thomas Hellstrom wrote: >>> On 08/31/2018 02:30 PM, Emil Velikov wrote: >>>> On 31 August 2018 at 12:54, Thomas Hellstrom <thellstrom at vmware.com> >>>> wrote: >>>>> To determine whether a device node is a drm device node or not, the code >>>>> currently compares the node's major number to the static drm major >>>>> device >>>>> number. >>>>> >>>>> This breaks the standalone vmwgfx driver on XWayland dri clients, >>>>> >>>> Any particular reason why the code doesn't use a fixed node there? >>>> It will make the diff vs the in-kernel driver a bit smaller. >>> Because then it won't be able to interoperate with other in-tree >>> drivers, like virtual drm drivers or passthrough usb drm drivers. >>> There is no clean way to share the minor number allocation with in-tree >>> drm, so standalone vmwgfx is using dynamic major allocation. >> I wonder why I haven't heard of any of these issues with the standalone >> version of amdgpu shipped in packaged AMD releases. Does that also use a >> different major number? If yes, maybe it's just that nobody has tried >> Xwayland clients with that driver. If no, how does it avoid the other >> issues described above? >> > AFAICT, the difference is that the standalone vmwgfx uses an internal > copy of drm core. > It doesn't reuse the in-kernel drm, hence it cannot know which minor it can use. > > -Emil Actually, standalone vmwgfx could perhaps also try to allocate minors from 63 and downwards. That might work, but needs some verification. /Thomas
