.TH WESTON-DRM 7 "2012-11-27" "Weston __version__"
.SH NAME
weston-drm \- the DRM backend for Weston
.SH SYNOPSIS
.B weston-launch
.LP
.B weston --backend=drm-backend.so
.
.\" ***************************************************************
.SH DESCRIPTION
The DRM backend is the native Weston backend for systems that support
the Linux kernel DRM, kernel mode setting (KMS), and evdev input devices.
It is the recommended backend for desktop PCs, and aims to provide
the full Wayland experience with the "every frame is perfect" concept.
It also relies on the Mesa GBM interface.

With the DRM backend,
.B weston
runs without any underlying windowing system. The backend uses the
Linux KMS API to detect connected monitors. Monitor hot-plugging is
supported. Input devices are found automatically by
.BR udev (7).
Compositing happens mainly in GL\ ES\ 2, initialized through EGL. It
is also possible to take advantage of hardware cursors and overlays,
when they exist and are functional. Full-screen surfaces will be
scanned out directly without compositing, when possible.
Hardware accelerated clients are supported via EGL.

The backend chooses the DRM graphics device first based on seat id.
If seat identifiers are not set, it looks for the graphics device
that was used in boot. If that is not found, it finally chooses
the first DRM device returned by
.BR udev (7).
Combining multiple graphics devices are not supported yet.

The DRM backend relies on
.B weston-launch
for managing input device access and DRM master status, so that
.B weston
can be run without root privileges. On switching away from the
virtual terminal (VT) hosting Weston, all input devices are closed and
the DRM master capability is dropped, so that other servers,
including
.BR Xorg (1),
can run on other VTs. On switching back to Weston's VT, input devices
and DRM master are re-acquired through the parent process
.BR weston-launch .
.
.\" ***************************************************************
.SH CONFIGURATION
.
The DRM backend uses the following entries from
.BR weston.ini .
.SS Section output
.TP
\fBname\fR=\fIconnector\fR
The KMS connector name identifying the output, for instance
.IR LVDS1 .
.TP
\fBmode\fR=\fImode\fR
Specify the video mode for the output. The argument
.I mode
can be one of the words
.BR off " to turn the output off, "
.BR preferred " to use the monitor's preferred video mode, or "
.BR current " to use the current video mode and avoid a mode switch."
It can also be a resolution as
\fIwidth\fBx\fIheight\fR, or a detailed mode line as below.
.TP
\fBmode\fR=\fIdotclock hdisp hsyncstart hsyncend htotal \
vdisp vsyncstart vsyncend vtotal hflag vflag\fR
Use the given detailed mode line as the video mode for this output.
The definition is the same as in
.BR xorg.conf "(5), and " cvt (1)
can generate detailed mode lines.
.TP
\fBtransform\fR=\fItransform\fR
Transform for the output, which can be rotated in 90-degree steps
and possibly flipped. Possible values are
.BR normal ", " 90 ", " 180 ", " 270 ", "
.BR flipped ", " flipped-90 ", " flipped-180 ", and " flipped-270 .
.
.\" ***************************************************************
.SH OPTIONS
.
When the DRM backend is loaded,
.B weston
will understand the following additional command line options.
.TP
.B \-\-current\-mode
By default, use the current video mode of all outputs, instead of
switching to the monitor preferred mode.
.TP
\fB\-\-drm\-device\fR=\fIcardN\fR
Use the DRM device
.I cardN
instead of the default heuristics based on seat assignments and boot VGA
status. For example, use
.BR card0 .
.TP
\fB\-\-seat\fR=\fIseatid\fR
Use graphics and input devices designated for seat
.I seatid
instead of the default seat
.BR seat0 .
.TP
\fB\-\-tty\fR=\fIx\fR
Launch Weston on tty
.I x
instead of using the current tty.
.
.\" ***************************************************************
.SH ENVIRONMENT
.
.TP
.B WESTON_TTY_FD
The file descriptor (integer) of the opened tty where
.B weston
will run. Set by
.BR weston-launch .
.TP
.B WESTON_LAUNCHER_SOCK
The file descriptor (integer) where
.B weston-launch
is listening. Automatically set by
.BR weston-launch .
.
.\" ***************************************************************
.SH "SEE ALSO"
.BR weston (1)
.\".BR weston-launch (1),
.\".BR weston.ini (5)