Xdmx
(1)
名称
Xdmx - head X server
用法概要
/usr/bin/Xdmx [:display] [option ...]
描述
User Commands Xdmx(1)
NAME
Xdmx - Distributed Multi-head X server
SYNOPSIS
/usr/bin/Xdmx [:display] [option ...]
DESCRIPTION
Xdmx is a proxy X server that uses one or more other X
servers as its display devices. It provides multi-head X
functionality for displays that might be located on differ-
ent machines. Xdmx functions as a front-end X server that
acts as a proxy to a set of back-end X servers. All of the
visible rendering is passed to the back-end X servers.
Clients connect to the Xdmx front-end, and everything
appears as it would in a regular multi-head configuration.
If Xinerama is enabled (e.g., with +xinerama on the command
line), the clients see a single large screen.
Xdmx communicates to the back-end X servers using the stan-
dard X11 protocol, and standard and/or commonly available X
server extensions.
OPTIONS
In addition to the normal X server options described in the
Xserver(1) manual page, Xdmx accepts the following command
line switches:
-display display-name
This specifies the name(s) of the back-end X server
display(s) to connect to. This option may be speci-
fied multiple times to connect to more than one
back-end display. The first is used as screen 0,
the second as screen 1, etc. If this option is
omitted, the $DISPLAY environment variable is used
as the single back-end X server display.
-xinput input-source
This specifies the source to use for XInput exten-
sion devices. The choices are the same as for
-input , described below, except that core devices
on backend servers cannot be treated as XInput
extension devices. (Although extension devices on
backend and console servers are supported as exten-
sion devices under Xdmx).
-input input-source
This specifies the source to use for the core input
devices. The choices are:
dummy
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A set of dummy core input drivers are used.
These never generate any input events.
local
The raw keyboard and pointer from the local com-
puter are used. A comma-separated list of
driver names can be appended. For example, to
select the example Linux keyboard and PS/2 mouse
driver use: -input local,kbd,ps2. The following
drivers have been implemented for Linux: kbd, ms
(a two-button Microsoft mouse driver), ps2 (a
PS/2 mouse driver), usb-mou (a USB mouse
driver), usb-kbd (a USB keyboard driver), and
usb-oth (a USB non-keyboard, non-mouse driver).
Additional drivers may be implemented in the
future. Appropriate defaults will be used if no
comma-separated list is provided.
display-name
If the display-name is a back-end server, then
core input events are taken from the server
specified. Otherwise, a console window will be
opened on the specified display.
If the display-name is followed by ",xi" then
XInput extension devices on the display will be
used as Xdmx XInput extension devices. If the
display-name is followed by ",noxi" then XInput
extension devices on the display will not be
used as Xdmx XInput extension devices. Cur-
rently, the default is ",xi".
If the display-name is followed by ",console"
and the display-name refers to a display that is
used as a backend display, then a console window
will be opened on that display and that display
will be treated as a backend display. Otherwise
(or if ",noconsole" is used), the display will
be treated purely as a backend or a console dis-
play, as described above.
If the display-name is followed by ",windows",
then outlines of the windows on the backend will
be displayed inside the console window. Other-
wise (or if ",nowindows" is used), the console
window will not display the outlines of backend
windows. (This option only applies to console
input.)
If the display-name is followed by ",xkb", then
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the next 1 to 3 comma-separated parameters will
specify the keycodes, symbols, and geometry of
the keyboard for this input device. For exam-
ple, ",xkb,xfree86,pc104" will specify that the
"xfree86" keycodes and the "pc104" symbols
should be used to initialize the keyboard. For
an SGI keyboard, ",xkb,sgi/indy(pc102)" might be
useful. A list of keycodes, symbols, and geome-
tries can be found in /usr/share/X11/xkb. Use
of keycodes, symbols and geometries for XKB con-
figuration is deprecated in favor of the rules,
layout, model, variant and options settings
available via the -param command line switch.
If this option is not specified, the input
device will be queried, perhaps using the XKEY-
BOARD extension.
If this option isn't specified, the default input
source is the first back-end server (the one used
for screen 0). The console window shows the layout
of the back-end display(s) and pointer movements and
key presses within the console window will be used
as core input devices.
Several special function keys are active, depending
on the input source:
Ctrl-Alt-q will terminate the Xdmx server in
all modes.
Ctrl-Alt-g will toggle a server grab in console
mode (a special cursor, currently a spider, is
used to indicate an active server grab).
Ctrl-Alt-f will toggle fine-grain motion in
console mode (a special cursor, currently a
cross hair, is used to indicate this mode). If
this mode is combined with a server grab, then
the cursor will have 4 lines instead of only 2.
Ctrl-Alt-F1 through Ctrl-Alt-F12 will switch to
another VC in local (raw) mode.
-shadowfb
This option turns on (legacy) support for the shadow
frame buffer.
-noshadowfb
This option turns off (legacy) support for the
shadow frame buffer. Note that this option has been
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deprecated and will be removed in the next release.
-nomulticursor
This option turns off support for displaying multi-
ple cursors on overlapped back-end displays. This
option is available for testing and benchmarking
purposes.
-fontpath
This option sets the Xdmx server's default font
path. This option can be specified multiple times
to accommodate multiple font paths. See the FONT
PATHS section below for very important information
regarding setting the default font path.
-configfile filename
Specify the configuration file that should be read.
Note that if the -display command-line option is
used, then the configuration file will be ignored.
-config name
Specify a configuration to use. The name will be
the name following the virtual keyword in the con-
figuration file.
-stat interval screens
This option enables the display of performance sta-
tistics. The interval is in seconds. The screens
is a count of the number of back-end screens for
which data is printed each interval. Specifying 0
for screens will display data for all screens.
For each screen, the following information is
printed: the screen number, an absolute count of the
number of XSync() calls made (SyncCount), the rate
of these calls during the previous interval
(Sync/s), the average round-trip time (in microsec-
onds) of the last 10 XSync() calls (avSync), the
maximum round-trip time (in microseconds) of the
last 10 XSync calls (mxSync), the average number of
XSync() requests that were pending but not yet pro-
cessed for each of the last 10 processed XSync()
calls, the maximum number of XSync() requests that
were pending but not yet processed for each of the
last 10 processed XSync() calls, and a histogram
showing the distribution of the times of all of the
XSync() calls that were made during the previous
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interval.
(The length of the moving average and the number and
value of histogram bins are configurable at compile
time in the dmxstat.h header file.)
-syncbatch interval
This option sets the interval in milliseconds for
XSync() batching. An interval less than or equal to
0 will disable XSync() batching. The default inter-
val is 100 ms.
-nooffscreenopt
This option disables the offscreen optimization.
Since the lazy window creation optimization requires
the offscreen optimization to be enabled, this
option will also disable the lazy window creation
optimization.
-nowindowopt
This option disables the lazy window creation opti-
mization.
-nosubdivprims
This option disables the primitive subdivision opti-
mization.
-noxkb Disable use of the XKB extension for communication
with the back end displays. (Combine with -kb to
disable all use of XKB.)
-depth int
This option sets the root window's default depth.
When choosing a default visual from those available
on the back-end X server, the first visual with that
matches the depth specified is used.
This option can be combined with the -cc option,
which specifies the default color visual class, to
force the use of a specific depth and color class
for the root window.
-norender
This option disables the RENDER extension.
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-noglxproxy
This option disables GLX proxy -- the build-in GLX
extension implementation that is DMX aware.
-noglxswapgroup
This option disables the swap group and swap barrier
extensions in GLX proxy.
-glxsyncswap
This option enables synchronization after a swap
buffers call by waiting until all X protocol has
been processed. When a client issues a glXSwap-
Buffers request, Xdmx relays that request to each
back-end X server, and those requests are buffered
along with all other protocol requests. However, in
systems that have large network buffers, this
buffering can lead to the set of back-end X servers
handling the swap buffers request asynchronously.
With this option, an XSync() request is issued to
each back-end X server after sending the swap
buffers request. The XSync() requests will flush
all buffered protocol (including the swap buffers
requests) and wait until the back-end X servers have
processed those requests before continuing. This
option does not wait until all GL commands have been
processed so there might be previously issued com-
mands that are still being processed in the GL pipe
when the XSync() request returns. See the -glxfin-
ishswap option below if Xdmx should wait until the
GL commands have been processed.
-glxfinishswap
This option enables synchronization after a swap
buffers call by waiting until all GL commands have
been completed. It is similar to the -glxsyncswap
option above; however, instead of issuing an
XSync(), it issues a glFinish() request to each
back-end X server after sending the swap buffers
requests. The glFinish() request will flush all
buffered protocol requests, process both X and GL
requests, and wait until all previously called GL
commands are complete before returning.
-ignorebadfontpaths
This option ignores font paths that are not avail-
able on all back-end servers by removing the bad
font path(s) from the default font path list. If no
valid font paths are left after removing the bad
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paths, an error to that effect is printed in the
log.
-addremovescreens
This option enables the dynamic addition and removal
of screens, which is disabled by default. Note that
GLXProxy and Render do not yet support dynamic addi-
tion and removal of screens, and must be disabled
via the -noglxproxy and -norender command line
options described above.
-param This option specifies parameters on the command
line. Currently, only parameters dealing with XKEY-
BOARD configuration are supported. These parameters
apply only to the core keyboard. Parameter values
are installation-dependent. Please see
/usr/share/X11/xkb or a similar directory for com-
plete information.
XkbRules
Defaults to "base". Other values may
include "sgi" and "sun".
XkbModel
Defaults to "pc105". When used with "base"
rules, other values may include "pc102",
"pc104", "microsoft", and many others. When
used with "sun" rules, other values may
include "type4" and "type5".
XkbLayout
Defaults to "us". Other country codes and
"dvorak" are usually available.
XkbVariant
Defaults to "".
XkbOptions
Defaults to "".
CONFIGURATION FILE GRAMMAR
The following words and tokens are reserved:
virtual display wall option param { } ; #
Comments start with a # mark and extend to the end of the
line. They may appear anywhere. If a configuration file is
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read into xdmxconfig, the comments in that file will be pre-
served, but will not be editable.
The grammar is as follows:
virtual-list ::= [ virtual-list ] | virtual
virtual ::= virtual [ name ] [ dim ] { dw-list }
dw-list ::= [ dw-list ] | dw
dw ::= display | wall | option
display ::= display name [ geometry ] [ / geometry ] [
origin ] ;
wall ::= wall [ dim ] [ dim ] name-list ;
option ::= option name-list ;
param ::= param name-list ;
param ::= param { param-list }
param-list ::= [ param-list ] | name-list ;
name-list ::= [ name-list ] | name
name ::= string | double-quoted-string
dim ::= integer x integer
geometry ::= [ integer x integer ] [ signed-integer
signed-integer ]
origin ::= @ integer x integer
The name following virtual is used as an identifier for the
configuration, and may be passed to Xdmx using the -config
command line option. The name of a display should be stan-
dard X display name, although no checking is performed
(e.g., "machine:0").
For names, double quotes are optional unless the name is
reserved or contains spaces.
The first dimension following wall is the dimension for
tiling (e.g., 2x4 or 4x4). The second dimension following
wall is the dimension of each display in the wall (e.g.,
1280x1024).
The first geometry following display is the geometry of the
screen window on the backend server. The second geometry,
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which is always preceeded by a slash, is the geometry of the
root window. By default, the root window has the same geom-
etry as the screen window.
The option line can be used to specify any command-line
options (e.g., -input). (It cannot be used to specify the
name of the front-end display.) The option line is pro-
cessed once at server startup, just line command line
options. This behavior may be unexpected.
CONFIGURATION FILE EXAMPLES
Two displays being used for a desktop may be specified in
any of the following formats:
virtual example0 {
display d0:0 1280x1024 @0x0;
display d1:0 1280x1024 @1280x0;
}
virtual example1 {
display d0:0 1280x1024;
display d1:0 @1280x0;
}
virtual example2 {
display "d0:0";
display "d1:0" @1280x0;
}
virtual example3 { wall 2x1 d0:0 d1:0; }
A 4x4 wall of 16 total displays could be specified as fol-
lows (if no tiling dimension is specified, an approximate
square is used):
virtual example4 {
wall d0:0 d1:0 d2:0 d3:0
d4:0 d5:0 d6:0 d7:0
d8:0 d9:0 da:0 db:0
dc:0 dd:0 de:0 df:0;
}
FONT PATHS
The font path used by the Xdmx front-end server will be
propagated to each back-end server,which requires that each
back-end server have access to the exact same font paths as
the front-end server. This can be most easily handled by
either using a font server (e.g., xfs) or by remotely mount-
ing the font paths on each back-end server, and then setting
the Xdmx server's default font path with the -I "-fontpath"
command line option described above.
For example, if you specify a font path with the following
command line:
Xdmx :1 -display d0:0 -fontpath /usr/fonts/75dpi/
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-fontpath /usr/fonts/Type1/ +xinerama
Then, /usr/fonts/75dpi/ and /usr/fonts/Type1/ must be valid
font paths on the Xdmx server and all back-end server, which
is d0 in this example.
Font servers can also be specified with the -fontpath
option. For example, let's assume that a properly config-
ured font server is running on host d0. Then, the following
command line
Xdmx :1 -display d0:0 -display d1:0 -fontpath
tcp/d0:7100 +xinerama
will initialize the front-end Xdmx server and each of the
back-end servers to use the font server on d0.
Some fonts might not be supported by either the front-end or
the back-end servers. For example, let's assume the front-
end Xdmx server includes support Type1 fonts, but one of the
back-end servers does not. Let's also assume that the
default font path for Xdmx includes Type1 fonts in its font
path. Then, when Xdmx initializes the default font path to
load the default font, the font path that includes Type1
fonts (along with the other default font paths that are used
by the Xdmx server) is sent to the back-end server that can-
not handle Type1 fonts. That back-end server then rejects
the font path and sends an error back to the Xdmx server.
Xdmx then prints an error message and exits because it
failed to set the default font path and was unable load the
default font.
To fix this error, the offending font path must be removed
from the default font path by using a different -fontpath
command line option.
The -fontpath option can also be added to the configuration
file as described above.
COMMAND-LINE EXAMPLES
The back-end machines are d0 and d1, core input is from the
pointer and keyboard attached to d0, clients will refer to
:1 when opening windows:
Xdmx :1 -display d0:0 -display d1:0 +xinerama
As above, except with core input from d1:
Xdmx :1 -display d0:0 -display d1:0 -input d1:0 +xin-
erama
As above, except with core input from a console window on
the local display:
Xdmx :1 -display d0:0 -display d1:0 -input :0 +xinerama
As above, except with core input from the local keyboard and
mouse:
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Xdmx :1 -display d0:0 -display d1:0 -input
local,kbd,ps2 +xinerama
Note that local input can be used under Linux while another
X session is running on :0 (assuming the user can access the
Linux console tty and mouse devices): a new (blank) VC will
be used for keyboard input on the local machine and the
Ctrl-Alt-F* sequence will be available to change to another
VC (possibly back to another X session running on the local
machine). Using Ctrl-Alt-Backspace on the blank VC will
terminate the Xdmx session and return to the original VC.
This example uses the configuration file shown in the previ-
ous section:
Xdmx :1 -input :0 +xinerama -configfile filename -con-
fig example2
With this configuration file line:
option -input :0 +xinerama;
the command line can be shortened to:
Xdmx :1 -configfile filename -config example2
USING THE USB DEVICE DRIVERS
The USB device drivers use the devices called
/dev/input/event0, /dev/input/event1, etc. under Linux.
These devices are driven using the evdev Linux kernel mod-
ule, which is part of the hid suite. Please note that if
you load the mousedev or kbddev Linux kernel modules, then
USB devices will appear as core Linux input devices and you
will not be able to select between using the device only as
an Xdmx core device or an Xdmx XInput extension device.
Further, you may be unable to unload the mousedev Linux ker-
nel module if XFree86 is configured to use /dev/input/mice
as an input device (this is quite helpful for laptop users
and is set up by default under some Linux distributions, but
should be changed if USB devices are to be used with Xdmx).
The USB device drivers search through the Linux devices for
the first mouse, keyboard, or non-mouse-non-keyboard Linux
device and use that device.
KEYBOARD INITIALIZATION
If Xdmx was invoked with -xkb or was not compiled to use the
XKEYBOARD extension, then a keyboard on a backend or console
will be initialized using the map that the host X server
provides.
If the XKEYBOARD extension is used for both Xdmx and the
host X server for the keyboard (i.e., the backend or console
X server), then the type of the keyboard will be obtained
from the host X server and the keyboard under Xdmx will be
initialized with that information. Otherwise, the default
type of keyboard will be initialized. In both cases, the
map from the host X server will not be used. This means
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that different initial behavior may be noted with and with-
out XKEYBOARD. Consistent and expected results will be
obtained by running XKEYBOARD on all servers and by avoiding
the use of xmodmap on the backend or console X servers prior
to starting Xdmx.
If -xkbmap is specified on the Xdmx command line, then that
map will currently be used for all keyboards.
MULTIPLE CORE KEYBOARDS
X was not designed to support multiple core keyboards. How-
ever, Xdmx provides some support for multiple core key-
boards. Best results will be obtained if all of the key-
boards are of the same type and are using the same keyboard
map. Because the X server passes raw key code information
to the X client, key symbols for keyboards with different
key maps would be different if the key code for each key-
board was sent without translation to the client. There-
fore, Xdmx will attempt to translate the key code from a
core keyboard to the key code for the key with the same key
symbol of the first core keyboard that was loaded. If the
key symbol appears in both maps, the results will be
expected. Otherwise, the second core keyboard will return a
NoSymbol key symbol for some keys that would have been
translated if it was the first core keyboard.
SEE ALSO
DMX(3), X(5), Xserver(1), xdmxconfig(1), vdltodmx(1),
xfs(1), xkbcomp(1), xkeyboard-config(5)
AUTHORS
Kevin E. Martin <kem@redhat.com>, David H. Dawes
<dawes@xfree86.org>, and Rickard E. (Rik) Faith <faith@red-
hat.com>.
Portions of Xdmx are based on code from The XFree86 Project
(http://www.xfree86.org) and X.Org (http://www.x.org).
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |x11/server/xdmx |
+-----------------------------+-----------------------------+
|Interface Stability |Volatile |
+-----------------------------+-----------------------------+
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