Otherwise drmModeAtomicCommit() in DrmOutput::doAtomicCommit() fails due
to unmatched buffer sizes.
While rendering continues working properly, this makes drm freak out and
try to go back to a previous state (see the test commit in
presentAtomically()) that in turn starts issuing screen events to every
process even though it's just to say the same thing. The fact that this
happens per frame makes the system unusable as soon as fullscreen starts
happening on a scaled display.
Another thing we could do is get EglGbmBackend::scanout() to take care
of the resizing.
This provides the compositor a way to indicate what output is being
rendered. The effects such as the screenshot can check the provided
screen object in order to function as expected.
If the file descriptor of the DRM device is greater than FD_SETSIZE, the
stack will be corrupted. However, it is highly unlikely that we ever hit
this case because DRM devices are opened at startup of kwin, so the file
descriptors should small.
In order to prevent the potential stack corruption, this change replaces
the usage of select() with poll().
Unlike select(), the api of poll() is much more sensible. Back 20 or so
years ago the main argument against poll() was that it's not implemented
by all platforms. But, nowadays, it's supported on all major platforms.
Otherwise if powerdevil for example is configured to turn screen off on
the power key press, we will turn it right back on when we get key
release event.
Suggested-by: David Edmundson <kde@davidedmundson.co.uk>
There are a couple of reasons not to use the lambda:
* It is unnecessary. The DrmGpu has the DRM file descriptor
* If a crash occurs somewhere in the lambda, the backtrace will be hard
to read
* Instead of processing events in the destructor of the DrmBackend
class, we should keep dispatching events without involving
QCoreApplication::processEvents() until all page flips are completed.
qEnvironmentVariableIntValue() will return 0 if the specified variable
is not set.
This means that swap events will be disabled on AMD GPUs unless the env
var is set explicitly to 1.
Once in a while, we receive complaints from other fellow KDE developers
about the file organization of kwin. This change addresses some of those
complaints by moving all of source code in a separate directory, src/,
thus making the project structure more traditional. Things such as tests
are kept in their own toplevel directories.
This change may wreak havoc on merge requests that add new files to kwin,
but if a patch modifies an already existing file, git should be smart
enough to figure out that the file has been relocated.
We may potentially split the src/ directory further to make navigating
the source code easier, but hopefully this is good enough already.
