the vmware svga video card emulated by qemu (qemu -vga vmware) complains and eventually causes a panic if the rectangles aren't clipped.
messages like the following can be observed from qemu before the kernel panics:
vmsvga_update_rect: update h was < 0 (-20000)
vmsvga_update_rect: update height too large y: 10000, h: 0
vmsvga_update_rect: update w was < 0 (-20000)
vmsvga_update_rect: update width too large x: 10000, w: 0
i could only reproduce this in qemu 2.0.50 on the master branch, when using the ui and had selected 'Zoom To Fit' from the View menu.
the software cursor starts flickering and reacts bumby if a process
spends most of its time with drawlock acquired because the timer interrupt
thats supposed to redraw the cursor fails to acquire the lock at the time
the timer fires.
instead of trying to draw the cursor on the screen from a timer interrupt
30 times per second, devmouse now creates a process calling cursoron() and
cursoroff() when the cursor needs to be redrawn. this allows the swcursor
to schedule a redraw while holding the drawlock in swcursoravoid() and
cursoron()/cursoroff() are now able to wait for a qlock (drawlock) because
they get called from process context.
the overall responsiveness is also improved with this change as the cursor
redraw rate isnt limited to 30 times a second anymore.
previously, we had to maintain 3 sets of pci vid/did's:
1) in /lib/vgadb for detection
2) in the userspace driver in aux/vga
3) in the kernel mode driver
this change makes the kernel mode driver more dumb in
the cases where possible. we let userspace do the pci
enumeration and if needed, it can set the pci address
of the vga card. kernel mode drivers can assume to get
the right pci device passed in scr->pci for enable()
and linear() functions and just do very basic sanity
checking before mapping framebuffer and mmio regions.
vgalinearpciid() was removed as userspace is responsible
to pick pci device.
theres a new vgactl message "pcidev" where userspace
can set the bus address. we initialize scr->pci in
vgareset() to the first pci graphics card found. this
should cover cases when an old aux/vga binary is used
that doesnt use the new pcidev message.
userspace drivers will now use the pci device that got
a match from /lib/vgadb and skip ther own enumeration.
this way, vga cards can be made to work by simply adding
an entry in vgadb with no need to modify userspace or
kernelspace drivers. this is not always possible if
the driver derives information from the specific card
model.
allow the shadow framebuffer (softscreen) to be used with any
vga driver, not just vesa. this removes the ugly scr->paddr = 0
hack employed by vesa driver to force softscreen and adds a
softscreen vgactl message that can switch the feature on and off
at runtime.
softscreen can greatly improve graphics performance when bus
reads are slow even tho it disables hardware acceleration.
