Red Hat ENTERPRISE LINUX 5.5 - TECHNICAL NOTES Manual page 292

Chapter 1. Package Updates
xorg-x11-qxl-drv is an X11 video driver for the QEMU QXL video accelerator. This driver makes it
possible to use Red Hat Enterprise Linux 5 as a guest operating system under KVM and QEMU, using
the SPICE protocol.
This update addresses the following:
* if a virtual machine running X11 was switched to run-level 3 and the startx command was then used
to restart X11, the X server would hang, resulting in a black screen. When "init 3" is run, the QXL
device switches into VGA mode without either notifying the X server or clearing the command buffer.
As a consequence, when X attempted to restart, the commands queued from the previous X session
(which are cleared when an X session is stopped properly and safely) cause X to hang and the virtual
machine to crash.
With this update the QXL driver now checks the device mode before issuing any commands: if the
QXL driver reports being in VGA mode, the driver now waits for it to be set back to non-VGA mode as
part of the normal X startup process. This avoids the problem created by the QXL device and ensures
the command queue is not left in an illegal state when exiting X.
* In the previous release, only a 32-bit x86 version of the QXL driver was included. With this update
both 32-bit and 64-bit x86 versions are
* Launching applications from shortcuts pinned to the task bar panel caused a visual glitch where
rectangles animating the movement of windows would persist on screen.
To improve performance and fix bugs in conjunction with moving windows around, the driver was
modified to keep damage in a separate pending_copy region. Accelerated operations then delete this
region, and whenever new damage appears, it is unioned onto the "to_be_sent" region, which is then
submitted at BlockHandler
This modification also resolves the following:
* Scrolling through a document with the mouse wheel in OpenOffice 3.1.1 would cause corruption of
the displayed document
* In Red Hat Enterprise Linux 5.4 with the KDE desktop running in a virtual machine using the QXL
driver, dragging icons or drawing frames on the desktop with the mouse would result in residual screen
corruption.(BZ#552838
* When running x11perf in a virtual machine with the 32-bit QXL driver, X Windows would occasionally
become unresponsive though the VM was responsive otherwise.
The 32-bit QXL driver did not implement correct memory accesses to the QXL ring buffer. This could
lead to an endless loop. In this update, all ring accesses have been modified to use volatile accessors.
The driver no longer enters an endless loop after this
* Unmapping errors and incorrect draw area values appeared in the log file.
This was caused by incorrect size parameters applied to xf86UnMapVidMem and printing of values
from incorrect memory structure. The size parameter was modified and ROM structure replaced QXL
structure for draw area values. These errors no longer appear in the
2203
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=509410
2204
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=543663
2205
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=544781
2206
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=552181
2207
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=552838
2208
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=549379
2209
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=549386
282
provided.(BZ#543663
2205
time.(BZ#544781
2206
text.(BZ#552181 )
2207
)
(BZ#509410
2204
)
)
modification.(BZ#549379
log.(BZ#549386
2203
)
2208
)
2209
)