[PATCH libdrm] libdrm: Allow dynamic drm majors on linux

[Michel Dänzer]

On 2018-08-31 4:46 p.m., Thomas Hellstrom wrote:
> On 08/31/2018 04:38 PM, Michel Dänzer 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?
>>
>>
> Is standalone AMD supposed to be able to coexist with in-tree drm drivers?

Yes, it does, it's working e.g. on laptops with an Intel integrated and
an AMD discrete GPU.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer