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Vincent Vanlaer 7bc43413ed Allow cursor render surface to be used as fb
In order for a surface to be used as a cursor plane framebuffer, it
appears that requiring the buffer to be linear is sufficient.

GBM_BO_USE_SCANOUT is added in case GBM_BO_USE_LINEAR isn't sufficient
on untested hardware.

Fixes #1323

Removed wlr_drm_plane.cursor_bo as it does not serve any purpose
anymore.

Relevant analysis (taken from the PR description):

While trying to implement a fix for #1323, I found that when exporting
the rendered surface into a DMA-BUF and reimporting it with
`GBM_BO_USE_CURSOR`, the resulting object does not appear to be valid.
After some digging (turning on drm-kms debugging and switching to legacy
mode), I managed to extract the following error: ```
[drm:__setplane_check.isra.1 [drm]] Invalid pixel format AR24
little-endian (0x34325241), modifier 0x100000000000001 ``` The format
itself refers to ARGB8888 which is the same format as
`renderer->gbm_format` used in master to create the cursor bo. However,
using `gbm_bo_create` with `GBM_BO_USE_CURSOR` results in a modifier of
0. A modifier of zero represents a linear buffer while the modifier of
the surface that is rendered to is  `I915_FORMAT_MOD_X_TILED` (see
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/include/uapi/drm/drm_fourcc.h?h=v4.20.6#n263).
In order to fix this mismatch in modifier, I added the
`GBM_BO_USE_LINEAR` to the render surface and everything started to work
just fine. I wondered however, whether the export and import is really
necessary. I then decided to test if the back buffer of the render
surface works as well, and at least on my hardware (Intel HD 530 and
Intel UHD 620) it does. This is the patch in this PR and this requires
no exporting and importing.

I have to note that I cheated in order to import DMA_BUFs into a cursor
bo when doing the first tests, since on import the Intel drivers check
that the cursor is 64x64. This is strange since cursor sizes other than
64x64 have been around for quite some time now
(https://lists.freedesktop.org/archives/mesa-commit/2014-June/050268.html).
Removing this check made everything work fine. I later (while writing
this PR) found out that `__DRI_IMAGE_USE_CURSOR` (to which
`GBM_BO_USE_CURSOR` translates) has been deprecated in mesa
(https://gitlab.freedesktop.org/mesa/mesa/blob/master/include/GL/internal/dri_interface.h#L1296),
which makes me wonder what the usecase of `GBM_BO_USE_CURSOR` is. The
reason we never encountered this is that when specifying
`GBM_BO_USE_WRITE`, a dumb buffer is created trough DRM and the usage
flag never reaches the Intel driver directly. The relevant code is in
https://gitlab.freedesktop.org/mesa/mesa/blob/master/src/gbm/backends/dri/gbm_dri.c#L1011-1089
. From this it seems that as long as the size, format and modifiers are
right, any surface can be used as a cursor.
2019-02-04 20:47:07 +01:00
.builds Update FreeBSD build 2019-01-07 08:26:16 +00:00
backend Allow cursor render surface to be used as fb 2019-02-04 20:47:07 +01:00
docs Introduce noop backend 2019-01-17 20:13:55 +10:00
examples Fix two issues found with Clang's static analyzer 2019-01-29 19:56:43 +01:00
include Allow cursor render surface to be used as fb 2019-02-04 20:47:07 +01:00
protocol Implement the pointer-gestures-unstable-v1 protocol 2019-01-28 22:06:36 +01:00
render Require libdrm >= 2.4.95 2019-01-29 19:33:38 +01:00
rootston rootston: only allow one drag icon per seat 2019-01-30 15:24:18 +01:00
tinywl tinywl/README: Fix misspelling. 2019-01-27 11:10:34 +01:00
types Merge pull request #1523 from emersion/set-same-selection-crash 2019-02-01 09:41:02 +01:00
util Use ftruncate to set shared memory object's size 2018-11-09 18:29:19 +01:00
xcursor xcursor: Support XDG user data dir location 2018-11-27 23:21:07 +01:00
xwayland data-device: make sources inert, rename cancel to destroy 2019-01-24 12:12:55 +01:00
.editorconfig Set .editorconfig ident_size 2019-01-25 11:37:46 +01:00
.gitignore update .gitignore 2018-03-03 15:23:26 +01:00
CONTRIBUTING.md util: add wlr_ prefix to log symbols 2018-07-09 22:49:54 +01:00
LICENSE Update LICENSE year (MIT license) 2018-04-12 21:29:59 -04:00
README.md Update READMEs per tinywl merge 2019-01-03 10:10:03 -05:00
glgen.sh Change how glgen.sh outputs files 2018-08-24 19:35:21 +12:00
meson.build meson: remove b_lundef=false on FreeBSD 2019-01-29 21:12:31 +01:00
meson_options.txt meson: yield xwayland option 2019-01-18 09:07:22 +01:00
wlroots.syms Remove symbol versioning from DSO 2018-07-20 11:09:56 +01:00

README.md

wlroots

Pluggable, composable, unopinionated modules for building a Wayland compositor; or about 50,000 lines of code you were going to write anyway.

  • wlroots provides backends that abstract the underlying display and input hardware, including KMS/DRM, libinput, Wayland, X11, and headless backends, plus any custom backends you choose to write, which can all be created or destroyed at runtime and used in concert with each other.
  • wlroots provides unopinionated, mostly standalone implementations of many Wayland interfaces, both from wayland.xml and various protocol extensions. We also promote the standardization of portable extensions across many compositors.
  • wlroots provides several powerful, standalone, and optional tools that implement components common to many compositors, such as the arrangement of outputs in physical space.
  • wlroots provides an Xwayland abstraction that allows you to have excellent Xwayland support without worrying about writing your own X11 window manager on top of writing your compositor.
  • wlroots provides a renderer abstraction that simple compositors can use to avoid writing GL code directly, but which steps out of the way when your needs demand custom rendering code.

wlroots implements a huge variety of Wayland compositor features and implements them right, so you can focus on the features that make your compositor unique. By using wlroots, you get high performance, excellent hardware compatibility, broad support for many wayland interfaces, and comfortable development tools - or any subset of these features you like, because all of them work independently of one another and freely compose with anything you want to implement yourself.

Check out our wiki to get started with wlroots.

wlroots is developed under the direction of the sway project. A variety of wrapper libraries are available for using it with your favorite programming language.

Building

Install dependencies:

  • meson
  • wayland
  • wayland-protocols
  • EGL
  • GLESv2
  • libdrm
  • GBM
  • libinput
  • xkbcommon
  • udev
  • pixman
  • systemd (optional, for logind support)
  • elogind (optional, for logind support on systems without systemd)
  • libcap (optional, for capability support)

If you choose to enable X11 support:

  • xcb
  • xcb-composite
  • xcb-xfixes
  • xcb-xinput
  • xcb-image
  • xcb-render
  • x11-xcb
  • xcb-errors (optional, for improved error reporting)
  • x11-icccm (optional, for improved Xwayland introspection)

Run these commands:

meson build
ninja -C build

Install like so:

sudo ninja -C build install

Contributing

See CONTRIBUTING.md.