On Fri, Sep 6, 2019 at 5:29 PM Tejun Heo tj@kernel.org wrote:
Hello,
On Wed, Sep 04, 2019 at 10:54:34AM +0200, Daniel Vetter wrote:
Anyway, I don't think reusing the drm_minor registration makes sense, since we want to be on the drm_device, not on the minor. Which is a bit awkward for cgroups, which wants to identify devices using major.minor pairs. But I guess drm is the first subsystem where 1 device can be exposed through multiple minors ...
Tejun, any suggestions on this?
I'm not extremely attached to maj:min. It's nice in that it'd be consistent with blkcg but it already isn't the nicest of identifiers for block devices. If using maj:min is reasonably straight forward for gpus even if not perfect, I'd prefer going with maj:min. Otherwise, please feel free to use the ID best for GPUs - hopefully something which is easy to understand, consistent with IDs used elsewhere and easy to build tooling around.
Block devices are a great example I think. How do you handle the partitions on that? For drm we also have a main minor interface, and then the render-only interface on drivers that support it. So if blkcg handles that by only exposing the primary maj:min pair, I think we can go with that and it's all nicely consistent. -Daniel