Some legacy drivers either don't accept gbm buffers suitable for cursors,
or don't handle them properly. In order to work around that, always do a
CPU import with legacy and use dumb buffers instead.
BUG: 453860
CCBUG: 456306
This behavior was added in order to fix a crash reported in bug report
442990. However, the analysis was not 100% correct, kwin failed to
create a placeholder because the relevant check was incorrect. The drm
backend was checking the list of all connected outputs rather than the
list with enabled outputs to decide whether to create a placeholder output.
As a safety measure the proposed behavior makes sense, however the drm
backend is not the right layer to implement it. If the last enabled
output is disconnected, kscreen should view it as a new output
setup and re-enable outputs in order to ask user what desired output
configuration should be.
The kernel doesn't disable connector objects that represent physical ports
when the output gets removed. If KWin tries to change the output configuration
without explicitly disabling the connector, atomic commits can fail.
Removing connectors that are still powered leads to a mismatch in atomic
commits: the crtc is still powered, but the connector also still there.
If KWin tries to disable the crtc afterwards, the atomic commits fail because
the connector needs to be disabled at the same time and it's missing from the
atomic commit request.
To fix this, whenever we fail to fetch information or get wrong data from
the kernel (like 0 modes), use the cached information instead and keep the
connector.
BUG: 456298
It seems it doesn't bring much and it may backfire. Especially don't
pass GBM_BO_USE_LINEAR as it will limit a lot the buffers that can be
created and GBM_BO_USE_RENDERING use seems to be more harmful than
helpful on most cases.
When we use a shadow buffer, we always render to the whole surface - setting
the damage region is incorrect and invokes undefined behavior. On the Lima
driver this caused flickering on screen rotation.
To fix this, don't set a damage region when we use a shadow buffer, which is
effectively setting the damage region to the full surface
It can happen that the drm backend temporarily lacks permission to do atomic
commits, or that the cached drm property values become out of sync with
the real values held by the kernel. Instead of failing with both, attempt
to update property values and try the commits again at a later time.
Set the time for mouse and touch events. This is especially important
for the mouse is as the timestamp will be used to discriminate between
single and double click. Previously this was always sending the double
click event, making buttons work only every other click.
BUG: 454275
BUG: 449907
At the moment, the DrmLeaseOutput class inherits from the
KWaylandServer::DrmLeaseConnectionV1Interface class. While this works,
it's not a future-proof design. For example, kwin could also lease its
"desktop" outputs in order to let another wayland compositor run
alongside it.
Also, it's a good practice to prefer composition over inheritance.
When dpms disabled outputs get set active, they require a modeset. If after
that they are set inactive again without resetting the pipelines first,
they no longer require a modeset but still have the pending properties that
would enable a crtc - but without a framebuffer set.
To prevent this, first test the current setup as it is, and only then see
if the pipelines would work if enabled again.
It makes it very hard to debug any use-case that isn't a strip of
outputs and even then, we should have other mechanisms to arrange
outputs properly (i.e. through kscreen).
