The recent addition of lockdep support to reservations and their subsequent
use by TTM showed up a number of potential problems with the way qxl was using
TTM objects.
a) it was allocating objects, and reserving them later without validating
underneath the reservation, which meant in extreme conditions the objects could
be evicted before the reservation ever used them.
b) it was reserving objects straight after allocating them, but with no
ability to back off should the reservations fail. It now allocates the necessary
objects then does a complete reservation pass on them to avoid deadlocks.
c) it had two lists per release tracking objects, unnecessary complicating
the reservation process.
This patch removes the dual object tracking, adds reservations ticket support
to the release and fence object handling. It then ports the internal fb
drawing code and the userspace facing ioctl to use the new interfaces properly,
along with cleanup up the error path handling in some codepaths.
Signed-off-by: Dave Airlie <airlied@redhat.com>
In order to fix an issue with reservations we need to create the releases
as pre-pinned objects, this changes the placement interface and bo creation
interface to allow creating pinned objects to save nested reservations later.
This is just a stepping stone to main fix which follows to actually fix how
qxl deals with reservations.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Now that the code is compatible in semantics, flip the switch.
Use ww_mutex instead of the homegrown implementation.
ww_mutex uses -EDEADLK to signal that the caller has to back off,
and -EALREADY to indicate this buffer is already held by the caller.
ttm used -EAGAIN and -EDEADLK for those, respectively. So some changes
were needed to handle this correctly.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
QXL is a paravirtual graphics device used by the Spice virtual desktop
interface.
The drivers uses GEM and TTM to manage memory, the qxl hw fencing however
is quite different than normal TTM expects, we have to keep track of a number
of non-linear fence ids per bo that we need to have released by the hardware.
The releases are freed from a workqueue that wakes up and processes the
release ring.
releases are suballocated from a BO, there are 3 release categories, drawables,
surfaces and cursor cmds. The hw also has 3 rings for commands, cursor and release handling.
The hardware also have a surface id tracking mechnaism and the driver encapsulates it completely inside the kernel, userspace never sees the actual hw surface
ids.
This requires a newer version of the QXL userspace driver, so shouldn't be
enabled until that has been placed into your distro of choice.
Authors: Dave Airlie, Alon Levy
v1.1: fixup some issues in the ioctl interface with padding
v1.2: add module device table
v1.3: fix nomodeset, fbcon leak, dumb bo create, release ring irq,
don't try flush release ring (broken hw), fix -modesetting.
v1.4: fbcon cpu usage reduction + suitable accel flags.
Signed-off-by: Alon Levy <alevy@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
