On 09/03/2018 06:33 PM, Daniel Vetter wrote:
On Mon, Sep 03, 2018 at 11:16:29AM +0200, Thomas Hellstrom wrote:
On 08/31/2018 05:30 PM, Thomas Hellstrom wrote:
On 08/31/2018 05:27 PM, Emil Velikov wrote:
On 31 August 2018 at 15:38, Michel Dänzer <michel@xxxxxxxxxxx> 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@xxxxxxxxxx>
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.
So unfortuntately this doesn't work since the in-tree drm's file operations
are registered with the DRM_MAJOR.
So I still think the patch is the way to go. If people are concerned that
also fbdev file descriptors are allowed, perhaps there are other sysfs
traits we can look at?
Somewhat out of curiosity, but why do you have to overwrite all of drm?
amdgpu seems to be able to pull their stunt off without ...
-Daniel
At the time we launched the standalone vmwgfx, the DRM <-> driver
interface was moving considerably more rapidly than the DRM <-> kernel
interface. I think that's still the case. Hence less work for us. Also
meant we can install the full driver stack with latest features on
fairly old VMs without backported DRM functionality.
/Thomas
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
