[PATCH] xserver: add udev/systemd multi-seat support
Lennart Poettering
lennart at poettering.net
Sat Jul 16 17:33:14 PDT 2011
Add support for multi-seat-aware input device hotplugging. This
implements the multi-seat scheme explained here:
http://www.freedesktop.org/wiki/Software/systemd/multiseat
This introduces a new X server switch "-seat" which allows configuration
of the seat to enumerate hotplugging devices on. If specified the value
of this parameter will also be exported as root window property Xorg_Seat.
To properly support input hotplugging devices need to be tagged in udev
according to the seat they are on. Untagged devices are assumed to be on
the default seat "seat0". If no "-seat" parameter is passed only devices
on "seat0" are used. This means that the new scheme is perfectly
compatible with existing setups which have no tagged input devices.
This also optimizes the udev code in away that is beneficial for systems
that do not support new udev/systemd style multi-seat: the patch makes
use of libudev functions to limit enumerating/monitoring of devices to
actual input devices. This should speed up start-up and minimize
wake-ups, since we will only enumerate/monitor the devices we are
interested in instead of all devices on the machine and all events they
generate.
Finally, this also unifies the code paths for the udev "change" and
"add" events, since these should be handled the same way in order to be
robust to "udevadm trigger" calls, or lost netlink messages. This also
simplifies the code.
Note that the -seat switch takes a completely generic identifier, and
that it has no effect on non-Linux systems. In fact, on other OSes a
completely different identifier scheme for seats could be used but still
be exposed with the Xorg_Seat and -seat.
I tried to follow the coding style of the surrounding code blocks if
there was any one could follow.
---
config/udev.c | 34 +++++++++++++++++++++++++++++-----
hw/xfree86/common/xf86Init.c | 19 +++++++++++++++++++
include/globals.h | 2 +-
os/utils.c | 10 ++++++++++
4 files changed, 59 insertions(+), 6 deletions(-)
diff --git a/config/udev.c b/config/udev.c
index 9ac34ee..b30f075 100644
--- a/config/udev.c
+++ b/config/udev.c
@@ -35,6 +35,7 @@
#include "hotplug.h"
#include "config-backends.h"
#include "os.h"
+#include "globals.h"
#define UDEV_XKB_PROP_KEY "xkb"
@@ -65,6 +66,7 @@ device_added(struct udev_device *udev_device)
struct udev_list_entry *set, *entry;
struct udev_device *parent;
int rc;
+ const char *dev_seat;
path = udev_device_get_devnode(udev_device);
@@ -73,6 +75,16 @@ device_added(struct udev_device *udev_device)
if (!path || !syspath)
return;
+ dev_seat = udev_device_get_property_value(udev_device, "ID_SEAT");
+ if (!dev_seat)
+ dev_seat = "seat0";
+
+ if (SeatId && strcmp(dev_seat, SeatId))
+ return;
+
+ if (!SeatId && strcmp(dev_seat, "seat0"))
+ return;
+
if (!udev_device_get_property_value(udev_device, "ID_INPUT")) {
LogMessageVerb(X_INFO, 10,
"config/udev: ignoring device %s without "
@@ -251,14 +263,12 @@ wakeup_handler(pointer data, int err, pointer read_mask)
return;
action = udev_device_get_action(udev_device);
if (action) {
- if (!strcmp(action, "add"))
- device_added(udev_device);
- else if (!strcmp(action, "remove"))
- device_removed(udev_device);
- else if (!strcmp(action, "change")) {
+ if (!strcmp(action, "add") || !strcmp(action, "change")) {
device_removed(udev_device);
device_added(udev_device);
}
+ else if (!strcmp(action, "remove"))
+ device_removed(udev_device);
}
udev_device_unref(udev_device);
}
@@ -283,6 +293,10 @@ config_udev_init(void)
if (!udev_monitor)
return 0;
+ udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "input", NULL);
+ if (strcmp(SeatId, "seat0"))
+ udev_monitor_filter_add_match_tag(udev_monitor, SeatId);
+
if (udev_monitor_enable_receiving(udev_monitor)) {
ErrorF("config/udev: failed to bind the udev monitor\n");
return 0;
@@ -291,11 +305,21 @@ config_udev_init(void)
enumerate = udev_enumerate_new(udev);
if (!enumerate)
return 0;
+
+ udev_enumerate_add_match_subsystem(enumerate, "input");
+ if (strcmp(SeatId, "seat0"))
+ udev_enumerate_add_match_tag(enumerate, SeatId);
+
udev_enumerate_scan_devices(enumerate);
devices = udev_enumerate_get_list_entry(enumerate);
udev_list_entry_foreach(device, devices) {
const char *syspath = udev_list_entry_get_name(device);
struct udev_device *udev_device = udev_device_new_from_syspath(udev, syspath);
+
+ /* Device might be gone by the time we try to open it */
+ if (!udev_device)
+ continue;
+
device_added(udev_device);
udev_device_unref(udev_device);
}
diff --git a/hw/xfree86/common/xf86Init.c b/hw/xfree86/common/xf86Init.c
index 15fdbc3..e3769eb 100644
--- a/hw/xfree86/common/xf86Init.c
+++ b/hw/xfree86/common/xf86Init.c
@@ -654,6 +654,25 @@ InitOutput(ScreenInfo *pScreenInfo, int argc, char **argv)
}
}
+ if (SeatId) {
+#define SEAT_ATOM_NAME "Xorg_Seat"
+ Atom SeatAtom;
+
+ SeatAtom = MakeAtom(SEAT_ATOM_NAME, sizeof(SEAT_ATOM_NAME) - 1, TRUE);
+
+ for (i = 0; i < xf86NumScreens; i++) {
+ int ret;
+
+ ret = xf86RegisterRootWindowProperty(xf86Screens[i]->scrnIndex,
+ SeatAtom, XA_STRING, 8,
+ strlen(SeatId)+1, SeatId );
+ if (ret != Success) {
+ xf86DrvMsg(xf86Screens[i]->scrnIndex, X_WARNING,
+ "Failed to register seat property\n");
+ }
+ }
+ }
+
/* If a screen uses depth 24, show what the pixmap format is */
for (i = 0; i < xf86NumScreens; i++) {
if (xf86Screens[i]->depth == 24) {
diff --git a/include/globals.h b/include/globals.h
index 8b80a65..17bca82 100644
--- a/include/globals.h
+++ b/include/globals.h
@@ -21,7 +21,7 @@ extern _X_EXPORT int defaultColorVisualClass;
extern _X_EXPORT int GrabInProgress;
extern _X_EXPORT Bool noTestExtensions;
-
+extern _X_EXPORT char *SeatId;
extern _X_EXPORT char *ConnectionInfo;
#ifdef DPMSExtension
diff --git a/os/utils.c b/os/utils.c
index 36cb46f..17869f0 100644
--- a/os/utils.c
+++ b/os/utils.c
@@ -201,6 +201,8 @@ Bool PanoramiXExtensionDisabledHack = FALSE;
int auditTrailLevel = 1;
+char *SeatId = NULL;
+
#if defined(SVR4) || defined(__linux__) || defined(CSRG_BASED)
#define HAS_SAVED_IDS_AND_SETEUID
#endif
@@ -511,6 +513,7 @@ void UseMsg(void)
ErrorF("-render [default|mono|gray|color] set render color alloc policy\n");
ErrorF("-retro start with classic stipple and cursor\n");
ErrorF("-s # screen-saver timeout (minutes)\n");
+ ErrorF("-seat string seat to run on\n");
ErrorF("-t # default pointer threshold (pixels/t)\n");
ErrorF("-terminate terminate at server reset\n");
ErrorF("-to # connection time out\n");
@@ -802,6 +805,13 @@ ProcessCommandLine(int argc, char *argv[])
else
UseMsg();
}
+ else if ( strcmp( argv[i], "-seat") == 0)
+ {
+ if(++i < argc)
+ SeatId = argv[i];
+ else
+ UseMsg();
+ }
else if ( strcmp( argv[i], "-t") == 0)
{
if(++i < argc)
--
1.7.6
Lennart
--
Lennart Poettering - Red Hat, Inc.
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