On Friday, June 3rd, 2022 at 16:38, Zack Rusin <zackr@xxxxxxxxxx> wrote: > > On Jun 3, 2022, at 10:32 AM, Simon Ser <contact@xxxxxxxxxxx> wrote: > > > > ⚠ External Email > > > > On Friday, June 3rd, 2022 at 16:27, Zack Rusin <zackr@xxxxxxxxxx> 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. > > I’m not sure what you mean here. They are broken right now. That’s what we’re > fixing. That’s the reason why the virtualized drivers are on deny-lists for > all atomic kms. So nothing needs to be updated. If you have a kms client that > was using virtualized drivers with atomic kms then mouse clicks never worked > correctly. > > So, yes, clients need to set cursor hotspot if they want mouse to work > correctly with virtualized drivers. My proposal was: - Introduce DRM_CLIENT_CAP_CURSOR_PLANE_NO_POSITION (or a better name). Only user-space which supports the hotspot props will enable it. - By default, don't expose a cursor plane, because current user-space doesn't support it (Weston might put a window in the cursor plane, and nobody can report hotspot). - If the KMS client enables the cap, advertise the cursor plane, and make it so the plane doesn't have the CRTC_X/CRTC_Y properties since the driver will pick the position. That way both old and new user-space are fixed. > >>> On Thursday, June 2nd, 2022 at 17:42, Zack Rusin zack@xxxxxxx 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. > > Yes, that’s what I said. There’s no way to differentiate between amdgpu that > doesn’t have those properties and virtio_gpu driver from a kernel before > hotspot properties were added. See cap proposal above.
