To get an image from KWin to the screen in the DRM pipeline we combine a CRTC,
an encoder and a connector. These objects are static in the sense, that they
represent real hardware on the graphics card, which doesn't change in a
session. See here for more details:
https://01.org/linuxgraphics/gfx-docs/drm/gpu/drm-kms.html
Until now we used DrmOutput as the main representation for such an active
rendering pipeline. I.e. it gets created and destroyed on hot plug events of
displays. On the other side we had no fixed representation of the static kernel
objects throughout the lifetime of KWin. This has several disadvantages:
* We always need to query all available static objects on an hot plug event.
* We can't manipulate the frame buffer of a CRTC after an output has been
disconnected
* Adding functionality for driving multiple displays on a single CRTC (i.e.
cloning) would be difficult
* We can't destroy the last frame buffer on display disconnect because the CRTC
still accesses it and have therefore a memory leak on every display disconnect
This patch solves these issues by storing representations of all available CRTC
and Connector objects in DrmBackend on init via DrmCrtc and DrmConnector
instances. On an hotplug event these vectors are looped for a fitting CRTC and
Connector combinations. Buffer handling is moved to the respective CRTC
instance. All changes in overview:
* Query all available CRTCs and Connectors and save for subsequent hotplug
events
* Fix logic errors in `queryResources()`
* Move framebuffers, buffer flip and blank logic in DrmCrtc
* Remove `restoreSaved()`. It isn't necessary and is dangerous if the old
framebuffer was deleted in the meantime. Also could reveal sensitive user
info from old session.
Test Plan:
Login, logout, VT switching, connect and disconnect external monitor, energy
saving mode.
Reviewers: #kwin
Subscribers: kwin, #kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D5118
Test Plan:
For the first time, actually plugged in my high DPI laptop.
Tested both 1x and 2x windows on 2 real displays one high DPI, one normal
Reviewers: #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D3498
The logic on page flips was inconsistent in the sense, that it should never
release a GBM buffer before it's not used (i.e. viewable on the display)
anymore. This happened unintended until now (on page flip we never really
did something useful in the else statement, because if we're here it's not
a GBM buffer anyway).
With this patch we:
* delete on page flips always only the old buffer, which is not used anymore
* release the buffer earlier on interrupts like display disconnect in order
to be able to destroy the EGL context
Test Plan:
Tested in non atomic mode (atomic mode is obsolete right now until my other
WIP patch D4539 is ready to be merged): Login, logout, suspend, normal use.
Reviewers: #kwin, graesslin
Reviewed By: #kwin, graesslin
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D5060
This is Milestone 1 of full support of Atomic Mode Setting (AMS) and
Universal Planes in the KWin DRM backend.
With Milestone 1 we can use the primary plane of a DRM output and do an
AMS commit (this means mode setting aswell as page flipping), if the
driver supports it. Until now the functionality is only tested on Intel
graphics. You need the drm-next kernel for most recent DRM kernel
developments. As boot option set "i915.nuclear_pageflip". Additionally
at the moment AMS is still hidden behind the environment variable
KWIN_DRM_AMS. Set it, if you want to try out AMS.
What needs to be done next: Make it possible to transfer EGL buffers
directly to planes and implement logic for deciding about using a plane
or not for a specific buffer.
You can read more about it on LWN:
https://lwn.net/Articles/653071
And on Martin's blog:
https://blog.martin-graesslin.com/blog/2015/08/layered-compositing/
I used as model previous work by Daniel Stone for Weston:
https://git.collabora.com/cgit/user/daniels/weston.git
Reviewed-by: mgraesslin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D2370
Summary:
If it's not possible to create a buffer to blank the output, KWin won't
be able to render to the output. In that case the output should not be
added to the list of outputs.
To support this DrmOutput::blank and DrmOutput::init return bool to
indicate whether they succeeded. DrmBackend handles this situation and
doesn't add the output to the list of outputs if init failed.
If after init there are no outputs KWin is in a state where it won't
be functional. Thus the platform emits the initFailed signal to
terminate.
BUG: 365242
FIXED-IN: 5.7.2
Test Plan: No hardware to reproduce the condition
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D2135
Summary:
Source code reorganization:
The base class AbstractBackend got renamed to Platform, thus the
"backends" are "platforms" now. As they are plugins they should go
together with other KWin plugins which are nowadays in the folder
plugins.
So new location is plugins/platforms/
Reviewers: #plasma, sebas
Subscribers: plasma-devel
Projects: #plasma
Differential Revision: https://phabricator.kde.org/D1353
