On Friday, June 3rd, 2022 at 16:27, Zack Rusin zackr@vmware.com wrote:
In particular: since the driver will ignore the KMS cursor plane position set by user-space, I don't think it's okay to just expose without opt-in from user-space (e.g. with a DRM_CLIENT_CAP).
cc wayland-devel and Pekka for user-space feedback.
I think Thomas expressed our concerns and reasons why those wouldn’t work for us back then. Is there something else you’d like to add?
I disagreed, and I don't understand Thomas' reasoning.
KMS clients will need an update to work correctly. Adding a new prop without a cap leaves existing KMS clients broken. Adding a cap allows both existing KMS clients and updated KMS clients to work correctly.
On Thursday, June 2nd, 2022 at 17:42, Zack Rusin zack@kde.org wrote:
- all userspace code needs to hardcore a list of drivers which require
hotspots because there's no way to query from drm "does this driver require hotspot"
Can you elaborate? I'm not sure I understand what you mean here.
Only some drivers require informations about cursor hotspot, user space currently has no way of figuring out which ones are those, i.e. amdgpu doesn’t care about hotspots, qxl does so when running on qxl without properly set cursor hotspot atomic kms will result in a desktop where mouse clicks have incorrect coordinates.
There’s no way to differentiate between drivers that do not care about cursor hotspots and ones that absolutely require it.
Only VM drivers should expose the hotspot properties. Real drivers like amdgpu must not expose it.