isMaster is not enough as long as we differ between master pointers and
keyboard. With flexible device classes, the usual checks for whether a
master device is a pointer (currently check for ->button, ->valuators or
->key) do not work as an SD may post an event through a master and mess this
check up.
Example, a device with valuators but no buttons would remove the button
class from the VCP and thus result in the
IsPointerDevice(inputInfo.pointer) == FALSE.
This will become worse in the future when new device classes are introduced
that aren't provided in the current system (e.g. a switch class).
This patch replaces isMaster with "type", one of SLAVE, MASTER_POINTER and
MASTER_KEYBOARD. All checks for dev->isMaster are replaced with an
IsMaster(dev).
dev->u.lastSlave was not signal safe since it was accessed by the DIX and
during signal handling.
Replaced with:
'dev->last.slave' for the signal handler's lastSlave (used to generate
DeviceChangedEvents), .
'dev->u.lastSlave' for the DIX lastSlave (currently only used in
change_modmap)
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
There's only two reasons for hierarchy events:
- device is added, removed, etc. In this case we want to send the event as
it happens.
- devices are added in a XIChangeDeviceHierarchy request. In this case we
only want one event cumulating all changes.
Rather than have one field per hierarchy change, XI2 has two fields - one
generic one and one per-device that include the device-specific flags.
This requires some funky handling for removed devices, but oh well.
Xephyr doesn't manually set Activate/DeactivateGrab for new devices,
resulting in a NULL-pointer dereference later when a grab is activated.
Avoid the segfault by ensuring that the pointer is always valid.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
A XTest virtual slave device pair (kbd/ptr) exists for every master
device pair. This is so XTest events are correctly propogated via slave
devices up to Master devices and the classes are correctly changed along
the way. We add the XTest slave device pair to the Virtual Core pointer
and provide a simple way of creating the devices.
A XTest Slave Device is identified by the XTstDevicePrivateKey property
being set in the devices devProperties
XI events are still propagated through the matching device, in the hope the
client knows what it is doing.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Allocating a slave device is essentially the same as allocating a master device.
Hence we rename AllocMaster to AllocDevicePair and provided the ability to
indicate if a master or slave device pair is required.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Some keyboards (?) advertise more than MAX_VALUATORS axes. Parts of the
internal event delivery relies on not having more than MAX_VALUATOR axes, so
let's cap it down.
If there's real devices that require more than the current 36, I'm sure we can
bump this up.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Some keyboards (?) advertise more than MAX_VALUATORS axes. Parts of the
internal event delivery relies on not having more than MAX_VALUATOR axes, so
let's cap it down.
If there's real devices that require more than the current 36, I'm sure we can
bump this up.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Virtually all callers use
XkbGetRulesDefault(&rmlvo);
InitKeyboardDeviceStruct(..., rmlvo);
Let's save them the trouble and accept NULL as a hint to take the
default RMLVO.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Benjamin Close <Benjamin.Close@clearchain.com>
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Split ChangeMasterDeviceClasses into an extra XISendDeviceChangedEvent that
assembles the XI2 wire event for the DeviceChanged event. Re-use this when
detaching the last SD.
Not quite perfect yet, we still copy the device classes from the slave now
rather than from the data we had when the event occured. But it's a start.
(We can now unexport SizeDeviceInfo and CopySwapDevices, not needed anymore)
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
0 is now reserved for the "AllDevices" virtual device.
1 is now reserved for the "AllMasterDevices" virtual device.
This also means that wherever we passed in (mskidx = 0), we now need to pass
in the deviceid.
This is just for correctness. The server should return BadValue for anything
not in [-100, 100].
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
If we have a busted xkb setup, the XKB initialization on the core devices
fails and leaves us with dev->key->xkbInfo == NULL. This in turn causes
segfaults lateron.
Return BadValue when the XKB configuration for a master device failed, and if
that happens for the VCP/VCK, die semi-gracefully.
The VCP init can only fail on OOM.
Reported by Aaron Plattner.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Daniel Stone <daniel@fooishbar.org>
Acked-by: Dan Nicholson <dbn.lists@gmail.com>
Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
devices.c: In function ‘DoChangeKeyboardControl’:
devices.c:1768: warning: ISO C90 forbids mixed declarations and code
Signed-off-by: Tomas Carnecky <tom@dbservice.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Instead of always keeping two copies of the keymap, only generate the
core keymap from the XKB keymap when we really need to, and use the XKB
keymap as the canonical keymap.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Replace both core and Xi functions with one function that validates the
proposed map, and sends out both kinds of notification.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Keyboard map notifications are always generated from within XKB code,
which also takes care of copying the keysyms, etc. If you need to
mangle the keymap yourself, generate a new core keymap/modmap, and pass
it to XkbApplyMappingChange.
SendMappingNotify is renamed to SendPointerMappingNotify (and ditto its
Device variants), which still only _sends_ the notifications, as opposed
to also doing the copying a la XkbApplyMappingChange.
Also have the modmap change code traverse the device hierachy, rather
than just going off the core keyboard.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Since modifierKeyMap is generated from modifierMap, just remove it, and
only generate it when we need to send the modifier map to the client.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
XkbInitKeyboardDeviceStruct is now the only valid keyboard
initialisation: all the details are hidden behind here. This now makes
it impossible to supply a core keymap at startup.
If dev->key is valid, dev->key->xkbInfo->desc is also valid.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
No more #ifdef XKB, because you can't disable the build, and no more
noXkbExtension either.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Note: properties don't need to be cleaned up, the DIX does it for us anyway.
Data that is stored in properties is cleaned up by the property system.
Handlers, etc. don't need to be unregistered while cleaning up, as they get
deleted when the device is removed anyway.
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
Signed-off-by: Simon Thum <simon.thum@gmx.de>
Currently, if a device map differs from the core pointer map, then the
request may return MappingBusy, even though all the affected core
buttons are in the up state.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Devices are only activated once - right after they've been added to the
server. If a device failes activation, it's dead. There's no reason to
continue. Return the error code from ActivateDevice() without setting up
sprite information or even sending a event to the client.
Then - in the DDX - just remove the device again.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
If a device hasn't been initialized, it doesn't have a cursor yet. So don't
set the cursor to the NullCursor, and don't try to DisableDevice either.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This still doesn't fix reset the MD's classes (a TODO that's been here for
ages), but at least we don't segfault anymore when detaching the last SD.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
A grep on xorg/* revealed there's no consumer of this define.
Quote Alan Coopersmith:
"The consumer was in past versions of the headers now located
in proto/x11proto - for instance, in X11R6.0's xc/include/Xproto.h,
all the event definitions were only available if NEED_EVENTS were
defined, and all the reply definitions required NEED_REPLIES.
Looks like Xproto.h dropped them by X11R6.3, which didn't have
the #ifdef's anymore, so these are truly ancient now."
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
Signed-off-by: Adam Jackson <ajax@redhat.com>
Save in a few special cases, _X_EXPORT should not be used in C source
files. Instead, it should be used in headers, and the proper C source
include that header. Some special cases are symbols that need to be
shared between modules, but not expected to be used by external drivers,
and symbols that are accessible via LoaderSymbol/dlopen.
This patch also adds conditionally some new sdk header files, depending
on extensions enabled. These files were added to match pattern for
other extensions/modules, that is, have the headers "deciding" symbol
visibility in the sdk. These headers are:
o Xext/panoramiXsrv.h, Xext/panoramiX.h
o fbpict.h (unconditionally)
o vidmodeproc.h
o mioverlay.h (unconditionally, used only by xaa)
o xfixes.h (unconditionally, symbols required by dri2)
LoaderSymbol and similar functions now don't have different prototypes,
in loaderProcs.h and xf86Module.h, so that both headers can be included,
without the need of defining IN_LOADER.
xf86NewInputDevice() device prototype readded to xf86Xinput.h, but
not exported (and with a comment about it).
Rather than assuming rules in the CoreKeyboardProc, init the default rules in
InitCoreDevices, then re-use them later.
In the xfree86 DDX, set the rules to "base" or "evdev", depending on whether
we'll load kbd or evdev.
If we create a new MD, use pc105,us as default and re-use the rules file used
previously.
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
The device's button down state array was changed to use DOWN_LENGTH and thus
bitflags for each button in cfcb3da7.
Update the DBSN events to copy this bit-wise state.
Update xkb and Xi to check for the bit flag instead of the array value.
Reported by ajax.
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
This is the biggest "visibility" patch. Instead of doing a "export"
symbol on demand, export everything in the sdk, so that if some module
fails due to an unresolved symbol, it is because it is using a symbol
not in the sdk.
Most exported symbols shouldn't really be made visible, neither
advertised in the sdk, as they are only used by a single shared object.
Symbols in the sdk (or referenced in sdk macros), but not defined
anywhere include:
XkbBuildCoreState()
XkbInitialMap
XkbXIUnsupported
XkbCheckActionVMods()
XkbSendCompatNotify()
XkbDDXFakePointerButton()
XkbDDXApplyConfig()
_XkbStrCaseCmp()
_XkbErrMessages[]
_XkbErrCode
_XkbErrLocation
_XkbErrData
XkbAccessXDetailText()
XkbNKNDetailMaskText()
XkbLookupGroupAndLevel()
XkbInitAtoms()
XkbGetOrderedDrawables()
XkbFreeOrderedDrawables()
XkbConvertXkbComponents()
XkbWriteXKBSemantics()
XkbWriteXKBLayout()
XkbWriteXKBKeymap()
XkbWriteXKBFile()
XkbWriteCFile()
XkbWriteXKMFile()
XkbWriteToServer()
XkbMergeFile()
XkmFindTOCEntry()
XkmReadFileSection()
XkmReadFileSectionName()
InitExtInput()
xf86CheckButton()
xf86SwitchCoreDevice()
RamDacSetGamma()
RamDacRestoreDACValues()
xf86Bpp
xf86ConfigPix24
xf86MouseCflags[]
xf86SupportedMouseTypes[]
xf86NumMouseTypes
xf86ChangeBusIndex()
xf86EntityEnter()
xf86EntityLeave()
xf86WrapperInit()
xf86RingBell()
xf86findOptionBoolean()
xf86debugListOptions()
LoadSubModuleLocal()
LoaderSymbolLocal()
getInt10Rec()
xf86CurrentScreen
xf86ReallocatePciResources()
xf86NewSerialNumber()
xf86RandRSetInitialMode()
fbCompositeSolidMask_nx1xn
fbCompositeSolidMask_nx8888x0565C
fbCompositeSolidMask_nx8888x8888C
fbCompositeSolidMask_nx8x0565
fbCompositeSolidMask_nx8x0888
fbCompositeSolidMask_nx8x8888
fbCompositeSrc_0565x0565
fbCompositeSrc_8888x0565
fbCompositeSrc_8888x0888
fbCompositeSrc_8888x8888
fbCompositeSrcAdd_1000x1000
fbCompositeSrcAdd_8000x8000
fbCompositeSrcAdd_8888x8888
fbGeneration
fbIn
fbOver
fbOver24
fbOverlayGeneration
fbRasterizeEdges
fbRestoreAreas
fbSaveAreas
composeFunctions
VBEBuildVbeModeList()
VBECalcVbeModeIndex()
TIramdac3030CalculateMNPForClock()
shadowBufPtr
shadowFindBuf()
miRRGetScreenInfo()
RRSetScreenConfig()
RRModePruneUnused()
PixmanImageFromPicture()
extern int miPointerGetMotionEvents()
miClipPicture()
miRasterizeTriangle()
fbPush1toN()
fbInitializeBackingStore()
ddxBeforeReset()
SetupSprite()
InitSprite()
DGADeliverEvent()
SPECIAL CASES
o defined as _X_INTERNAL
xf86NewInputDevice()
o defined as static
fbGCPrivateKey
fbOverlayScreenPrivateKey
fbScreenPrivateKey
fbWinPrivateKey
o defined in libXfont.so, but declared in xorg/dixfont.h
GetGlyphs()
QueryGlyphExtents()
QueryTextExtents()
ParseGlyphCachingMode()
InitGlyphCaching()
SetGlyphCachingMode()
I merged the wrong patch. See correct patch at:
http://lists.freedesktop.org/archives/xorg/2008-November/040540.html
Not activating the device before attempting to enable it would leave the
sprite unset, crashing the server when enabling the real devices.
This reverts commit e078901a4e.
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
As proposed by Owen Taylor [1], the enter-leave event model needs to adjust
the events sent to each window depending on the presence of pointers in a
window, or in a subwindow.
The new model can be summarised as:
- if the pointer moves into or out of a window that has a pointer in a child
window, the events are modified to appear as if the pointer was moved out of
or into this child window.
- if the pointer moves into or out of a window that has a pointer in a parent
window, the events are modified to appear as if the pointer was moved out of
or into this parent window.
Note that this model requires CoreEnterLeaveEvent and DeviceEnterLeaveEvent to
be split and treated separately.
[1] http://lists.freedesktop.org/archives/xorg/2008-August/037606.html
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Adam Jackson <ajax@redhat.com>
EnableDevice and DisableDevice both change the property too.
And enabled must be set to FALSE in AddInputDevice, the device is not enabled
yet.
X.Org Bug 18111 <https://bugs.freedesktop.org/show_bug.cgi?id=18111>
dev->enabled is a Bool. Bool is two bytes.
BOOL on the other hand is a protocol type and always 1 byte. So copy the value
into the one-byte type before passing it into XIChangeDeviceProperty.
Found by Michel Dänzer.
X.Org Bug 18111 <http://bugs.freedesktop.org/show_bug.cgi?id=18111>
The current code exposes to inconsistent updates, i.e. if handler N succeeds
but handler N+1 fails in setting the property, an error is returned to the
client although parts of the server now behave as if the property change
succeeded.
This patch adds a "checkonly" parameter to the SetProperty handler. The
handlers are then called twice, once with checkonly set to TRUE.
On the checkonly run, handlers _MUST_ return error codes if the property
cannot be applied. Handlers are not permitted to actually apply the changes.
On the second run, handlers are permitted to apply property changes.
Errors codes returned on the second run are ignored.
A property can only be deleted if any of the following is true:
- if a property is deletable and all handlers return Success.
- if a property is non-deleteable and the all handlers return Success AND the
delete request does not come from a client (i.e. driver or the server).
A client can never delete a non-deletable property.
For master devices, the ptraccel code could segfault on free since we'd be
dereferencing random memory. Callocing the valuatorClassRec is the easy fix.
Unplug a mouse, then warp the pointer and the warp pointer code will try
to update the position of the last slave device associated with the
master. That pointer will be stale and the X server will crash.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
We may need more than one handler to deal with a property (e.g. one in the
driver, one in the DIX), so get the handlers into a linked list and call them
one-by-one. This is of course slightly less entertaining than the hilarious
WRAP/UNWRAP game we play in other parts of the server.
XIRegisterPropertyHandler/XIUnregisterPropertyHandler are the interface
drivers/the DIX should use to attach themselves to the device.
XIDeleteAllDeviceProperties destroys everything, including the handlers.
Basically just copied from randr properties, with minor changes only.
Each device supports arbitrary properties that can be modified by clients.
Modifications to the properties are passed to the driver (if applicable) and
can then affect the configuration of the device.
Note that device properties are limited to a specific device. A property set
on a slave device does not migrate to the master.
Basically just copied from randr properties, with minor changes only.
Each device supports arbitrary properties that can be modified by clients.
Modifications to the properties are passed to the driver (if applicable) and
can then affect the configuration of the device.
Note that device properties are limited to a specific device. A property set
on a slave device does not migrate to the master.
Using id = 0 only worked pre-MPX since XInput didn't allow XOpenDevice for the
core devices (0 and 1). Now we can now legally register for events so we may
overwrite our device-independent classes with the ones selected for the VCP.
So, increase the EMASKSIZE to MAX_DEVICES + 1 and use MAX_DEVICES as the ID
when we don't have a device.
Mixing usage where some parts of the code treated this field as a bitmask
and other parts as an array of card8 was wrong, and as the wire protocol
wanted bitmasks, it was less invasive to switch the newer counting code use
booleans.
Master devices track slave buttons by waiting for all slave buttons to be
released before delivering the release event to the client.
This also removes the state merging code in DeepCopyDeviceClasses -- that
code was changing master device state without delivering any events,
violating protocol invariants. The result will be that existing slave
button state which does not match the master will not be visible through the
master device. Fixing this would require that we synthesize events in this
function, which seems like a bad idea. Note that keyboards have the same
issue.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter@cs.unisa.edu.au>
device->button->down used to be a 32-byte bitmask with one bit for each
button. This has changed into a 256-byte array, with one byte assigned for
each button. Some of the callers were still using this array as a bitmask
however, this is fixed with this patch.
Thanks to Keith Packard for pointing this out. See also:
http://lists.freedesktop.org/archives/xorg/2008-June/036202.html
We only have one set of default rules options in xkb. When the second keyboard
is brought up with Xkb options specified, these new options overwrite the old.
In future server generations, the rules used for the VCK are a mixture of the
default ones and ones previously specified for other keyboards. Simply
resetting the xkb default rules to NULL avoids this issue.
Reproducable by setting XkbLayout "de" and XkbVariant "nodeadkeys". In the
second server generation, the VCK has "us(nodeadkeys)". This again produces a
SIGABRT when the first key is hit.
I could not figure out why the SIGABRT happens. This patch is avoiding the
issue rather than fixing it.
With the MD/SD device hierarchy we need control over the generation of the
motion history as well as the conversion later before posting it to the
client. So let's not let the drivers change it.
No x.org driver currently uses it anyway, linuxwacom doesn't either so dumping
it seems safe enough.
During GetPointerEvents (and others), we need to access the last coordinates
posted for this device from the driver (not as posted to the client!). Lastx/y
is ok if we only have two axes, but with more complex devices we also need to
transition between all other axes.
ABI break, recompile your input drivers.
Sometimes we didn't have a cursor when coming back from suspend. Reason was
that the suspend caused the server to lose the device that was attached to the
VCP, and a RemoveDevice() would then set the cursor to NULL.
Solution: only set the cursor to NULL if we actually own the sprite.
We pass in the client that wants to create the device anyway, lets use the
parameter instead of hardcoding the serverClient.
Wow. I hope this is merge detritus, otherwise it'd be a sign that I didn't
have enough coffee that day.
When a new device is added, calculate the event size needed if a DCCE event is
sent and set the EQ's event size to this minimum. This avoids reallocs when a
event is sent (which may happen during a SIGIO).
This variable was used originally to determine which client is allowed to
change the pointer-keyboard pairing. For now, we just let anyone change it and
see how that works out.
Rather than freeing/allocing classes each time the device capabilities need to
swap, store them in the devPrivates system.
When a class is unused, it is pushed into the devPrivates, and later recovered
when needed again. This saves us a lot of memory allocations/frees, admittedly
on the cost of some memory.
The DDX (xfree86 anyway) maintains its own device list in addition to the one
in the DIX. CloseDevice will only remove it from the DIX, not the DDX. If the
server then restarts (last client disconnects), the DDX devices are still
there, will be re-initialised, then the hal devices come in and are added too.
This repeats until we run out of device ids.
This also requires us to strdup() the default pointer/keyboard in
checkCoreInputDevices.
X.Org Bug 14418 <http://bugs.freedesktop.org/show_bug.cgi?id=14418>
The device classes aren't deleted anymore on a class change, so there's no
need to store the MD's original classes. We should however restore the MD to
sane defaults when disconnecting the last device, consider this as TODO item.
Instead of a simple counter, use bits to keep track of which device is where
etc. When device enters a window (or sets focus), the bit matching the device
is set, when it leaves again, it is unset. If there are 0 bits set, then
Leave/Enter/Focus events may be sent to the client.
Same theory as before, but this should get around the insanity with
Grab/Ungrab special cases. Those cases are basically untested though.
InitializeSprite won't create a new one if it already exists, with the result
of overwriting the master's sprite. This master sprite is then assigned to the
floating slave, and freed when the slave is reattached later.
Setting the sprite to NULL forces InitializeSprite to alloc a new one, and
this one can be freed without further repercussions.
XkbFinishDeviceInit does the following:
xkbi->kbdProc= pXDev->kbdfeed->CtrlProc;
pXDev->kbdfeed->CtrlProc= XkbDDXKeybdCtrlProc;
If we directly copy the device classes for the VCK, pXDev->kbdfeed->CtrlProc
at the time of copying is still XbkDDXKeybdCtrlProc. So at some point
XkbDDXKeybdCtrlProc is called, and calls itself, and calls itself, and...
Setting the device's classes to NULL seems to fix things. The memory isn't
lost, it gets stored into the devPrivates and freed at device closing time.
Before we enable the device through the driver, we size it up and make sure
that the events in the event list contain enough bytes for a possible
ClassesChangedEvent lateron.
If two devices are attached to the same master device, pressing button 1 on
each of them leads to two button presses from the same device. Some apps
really don't like that.
So we just put a counter in place and only send the first press and the last
release.
We free the ValuatorClassRec quite regularly. If a SIGIO is handled while
we're swapping device classes, we can bring the server down when we try to
access lastx/lasty of the master device.
XkbInitKeyboardDefviceStruct may call FatalError if it fails. FatalError then
cleans up all the devices, resulting in a segfault if the pointer is
uninitialised.
Old code was fundamentally broken, fixes now are:
- free the MDs current device classes
- copy the device classes instead of flipping the pointers
- check for the old MD, not the new one.
Anything in dev->key, dev->valuator etc. of a MD must always be a copy of the
original class. The intial classes of an MD (the ones set up before an SD is
attached) as well, as we may have to restore them if no SD is attached
anymore.
Each time a different slave device sends through a master, an
DeviceClassesChangedEvent is enqueued. When this event is processed, all
classes of the matching master device are changed, and the event is sent to
the clients.
Next time the master is queried, it thus shows the evclasses of the last slave
device. The original classes are stored in the devPrivates.
TODO: if all slave devices are removed, the master's original classes need to
be restored.
For pointers: don't try to set master->valuator fields if there is no master.
For keyboards: check if device is valid before trying to access the fields in
miPointerGetScreen (btw. this disables DGA events for floating keyboards).
Also stop the hideous number of ErrorFs if we request the paired device for a
floating dev.
XkbRemoveResourceClient wants to access xkbInfo if it exists, so make
sure we NULL it after freeing it. It doesn't make much sense to move
the RemoveResourceClient call first, as there's not much point in
notifying clients while we're shutting the server down anyway.
