Re: Atomic KMS API lacks the ability to set cursor hot-spot coordinates

["Michel Dänzer" <michel@daenzer.net>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 2020-03-19 1:54 p.m., Pekka Paalanen wrote:
> On Thu, 19 Mar 2020 12:52:14 +0100 Hans de Goede
> <hdegoede@redhat.com> wrote:
>> On 3/19/20 12:35 PM, Michel Dänzer wrote:
>>> On 2020-03-18 4:22 p.m., Simon Ser wrote:
>>>>>
>>>>> On 3/18/20 3:38 PM, Simon Ser wrote:
>>>>>>
>>>>>>> 1) Letting the VM-viewer window-system draw the cursor
>>>>>>> as it normally would draw it.
>>>>>>
>>>>>> Why is this important? Can't the VM viewer hide the
>>>>>> cursor and use a sub-surface to manually draw the cursor
>>>>>> plane configured by the guest?
>>>>>
>>>>> Because then moving the cursor as seen by the user requires
>>>>> a round trip through the VM and that adds latency, esp.
>>>>> when the VM viewer is viewing a VM which is running
>>>>> somewhere else over the network.
>>>>
>>>> The video output has latency anyway.
>>>
>>> Sounds like you've never tried the two different modes
>>> yourself? :) IME it makes a big difference even with a local
>>> VM. Even very little latency can make the cursor feel awkward,
>>> like it's being held back by a rubber band or something.
>>
>> Right not to mention that the latency may be variable, so the
>> cursor moves in a jittery fashion instead of having it move
>> smoothly matching the smooth way a user normally moves the
>> mouse.
>>
>> This totally wrecks hand-eye coordination and is just plain
>> awefull.
>
> I have experienced it, and while it is painful, I prefer that pain
> over the pain of accidentally clicking something that was not
> transmitted to the remote display yet.

Unless you mean clicking something while the cursor is moving, not
sure how seamless vs not affects this, since the delay of something
appearing on the remote display should be the same in both cases?


> Therefore I think the best user experience is to use both types of
> cursor at the same time: the remote desktop or VM viewer paints
> the local cursor as an aid, like a phantom, and the cursor from
> inside the VM is also visible with the latency it naturally has.
> That means I could actually see that the screen has caught up with
> my motions before I click something.

I'd expect that to result in "duplicate cursor" bug reports — I'd
certainly consider it a bug with my user hat on.


- -- 
Earthling Michel Dänzer               |               https://redhat.com
Libre software enthusiast             |             Mesa and X developer
-----BEGIN PGP SIGNATURE-----

iF0EARECAB0WIQSwn681vpFFIZgJURRaga+OatuyAAUCXnN45gAKCRBaga+Oatuy
AEMOAJsEtOvBJIA6CGHOmwrp7SFd9M3o2wCfcCs7lCrCNsHxAels/4YUXm5FJas=
=FfIQ
-----END PGP SIGNATURE-----
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel