The buffer release queue has two kinds of entries:
* Pending async flips.
* Completed flips waiting for their buffer to be released by the Wayland
compositor.
xwl_present_timer_callback neither completes async flips nor releases
buffers, so the timer isn't needed for the buffer release queue.
Fixes issue #12. Presumably the problem was that Present operations on
unmapped windows were executed immediately instead of only when reaching
the target MSC.
When a window is unrealized, a pending frame callback may never be
called, which could result in repeatedly freezing until the frame timer
fires after a second.
Fixes these symptoms when switching from fullscreen to windowed mode in
sauerbraten.
There's no need to keep track of the window which last performed a
Present flip. This fixes crashes due to the assertion in
xwl_present_flips_stop failing. Fixes issue #10.
The damage generated by a flip only needs to be ignored once, then
xwl_window::present_flipped can be cleared. This may fix freezing in
the (hypothetical) scenario where Present flips are performed on a
window, followed by other drawing requests using the window as the
destination, but nothing triggering xwl_present_flips_stop. The damage
from the latter drawing requests would continue being ignored.
Completing them from xwl_present_sync_callback had at least two issues:
* It was before the MSC was incremented in xwl_present_frame_callback,
so the MSC value in the completion event could be lower than the
target specified by the client. This could cause hangs with the Mesa
Vulkan drivers.
* It allowed clients to run at a frame-rate higher than the Wayland
compositor's frame-rate, wasting energy on generating frames which
were never displayed. This isn't expected to happen unless the client
specified PresentOptionAsync (in which case flips are still completed
from xwl_present_sync_callback, allowing higher frame-rates).
v2:
* Make xwl_present_has_events return true when there's a pending
"synchronous" flip, so those complete after at most ~1 second even if
the Wayland server doesn't send a frame event.
Bugzilla: https://bugs.freedesktop.org/106713
Apart from simplifying the code, this should also prevent a condition
(which might only be possible with the following fix) reported in
https://gitlab.freedesktop.org/wayland/weston/issues/115#note_52467:
1. xwl_present_timer_callback indirectly calls xwl_present_reset_timer
-> xwl_present_free_timer
2. xwl_present_timer_callback then returns a non-0 value, so DoTimer
calls TimerSet with the old xwl_present_window->frame_timer pointer
which was freed in step 1 => use after free
Calling xwl_present_reset_timer explicitly passes NULL to TimerSet if
step 1 freed xwl_present_window->frame_timer, and it will allocate a new
one.
`xwl_present_timer_callback()` is initially marked a private and later
implemented as public.
Let's keep that private, shall we.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Xwayland's `xwl_destroy_window()` invokes `xwl_present_cleanup()`
before the common `DestroyWindow()`.
But then `DestroyWindow()` calls `present_destroy_window()` which will
possibly end up in `xwl_present_abort_vblank()` which will try to access
data that was previously freed by `xwl_present_cleanup()`:
Invalid read of size 8
at 0x434184: xwl_present_abort_vblank (xwayland-present.c:378)
by 0x53785B: present_wnmd_abort_vblank (present_wnmd.c:651)
by 0x53695A: present_free_window_vblank (present_screen.c:87)
by 0x53695A: present_destroy_window (present_screen.c:152)
by 0x42A90D: xwl_destroy_window (xwayland.c:653)
by 0x584298: compDestroyWindow (compwindow.c:613)
by 0x53CEE3: damageDestroyWindow (damage.c:1570)
by 0x4F1BB8: DbeDestroyWindow (dbe.c:1326)
by 0x46F7F6: FreeWindowResources (window.c:1031)
by 0x472847: DeleteWindow (window.c:1099)
by 0x46B54C: doFreeResource (resource.c:880)
by 0x46C706: FreeClientResources (resource.c:1146)
by 0x446ADE: CloseDownClient (dispatch.c:3473)
Address 0x182abde0 is 80 bytes inside a block of size 112 free'd
at 0x4C2FDAC: free (vg_replace_malloc.c:530)
by 0x42A937: xwl_destroy_window (xwayland.c:647)
by 0x584298: compDestroyWindow (compwindow.c:613)
by 0x53CEE3: damageDestroyWindow (damage.c:1570)
by 0x4F1BB8: DbeDestroyWindow (dbe.c:1326)
by 0x46F7F6: FreeWindowResources (window.c:1031)
by 0x472847: DeleteWindow (window.c:1099)
by 0x46B54C: doFreeResource (resource.c:880)
by 0x46C706: FreeClientResources (resource.c:1146)
by 0x446ADE: CloseDownClient (dispatch.c:3473)
by 0x446DA5: ProcKillClient (dispatch.c:3279)
by 0x4476AF: Dispatch (dispatch.c:479)
Block was alloc'd at
at 0x4C30B06: calloc (vg_replace_malloc.c:711)
by 0x433F46: xwl_present_window_get_priv (xwayland-present.c:54)
by 0x434228: xwl_present_get_crtc (xwayland-present.c:302)
by 0x539728: proc_present_query_capabilities (present_request.c:227)
by 0x4476AF: Dispatch (dispatch.c:479)
by 0x44B5B5: dix_main (main.c:276)
by 0x75F611A: (below main) (libc-start.c:308)
This is because `xwl_present_cleanup()` frees the memory but does not
remove it from the window's privates, and `xwl_present_abort_vblank()`
will still find it and hence try to access that freed memory...
Remove `xwl_present_window` from window's privates on cleanup so that no
other function can find and reuse that data once it's freed.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1616269
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
When retrieving the Wayland buffer from a pixmap, if the buffer already
exists, the GBM backend will return that existing buffer.
However, as seen with the Present issues, if the call had previously
passed a wrong size, that buffer will remain at the wrong size for as
long as the buffer exists, which is error prone.
Considering that the width/height passed to get_wl_buffer() is always the
actual pixmap drawable size, and considering that the EGLStream backend
makes no use of the size either, there is really no point in passing the
width/height around.
Simplify the xwl_glamor_pixmap_get_wl_buffer() and EGL backends API by
removing the pixmap size, and use the drawable size instead.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Now that we have separate backends for EGLStream and GBM, we can
explicitly check for the EGLStream backend to disable present support
in that case.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
To be able to check for availability of the Wayland interfaces required
to run a given EGL backend (either GBM or EGLStream for now), we need
to have each backend structures and vfuncs in place before we enter the
Wayland registry dance.
That basically means that we should init all backends at first, connect
to the Wayland compositor and query the available interfaces and then
decide which backend is available and should be used (or none if either
the Wayland interfaces or the EGL extensions are not available).
For this purpose, hold an egl_backend struct for each backend we are to
consider prior to connect to the Wayland display so that, when we get to
query the Wayland interfaces, everything is in place for each backend to
handle the various Wayland interfaces.
Eventually, when we need to chose which EGL backend to use for glamor,
the available Wayland interfaces and EGL extensions available are all
known to Xwayland.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
If the pixmap size does not match the present box size, flickering
occurs.
This can happen when the client changes its size (e.g. switching to
fullscreen), and since the buffer is kept as long as the pixmap is
valid, once the buffer is created, it remains at the wrong (old) size
and causes continuous flickering.
Use the actual pixmap's drawable size instead of the present box to
create the buffer so that it's sized appropriately.
Bugzilla: https://bugs.freedesktop.org/106841
Fixes: 0fb2cca193 "xwayland: Preliminary support for Present's new
window flip mode"
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Roman Gilg <subdiff@gmail.com>
We probably don't want a fake crtc to be visible to clients, and we
definitely don't want to generate events every time we create such a
fake (which would happen as a side effect from RRCrtcCreate hitting
RRTellChanged). As it happens we're not actually using that crtc for
anything because xwayland doesn't store any state on the crtc object,
so it suffices to use the real crtc for the screen.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Tested-by: Roman Gilg <subdiff@gmail.com>
Reviewed-by: Roman Gilg <subdiff@gmail.com>
Instead of reusing xwl_window introduce a persistent window struct for every
window, that asks for Present flips.
This struct saves all relevant data and is only freed on window destroy.
Signed-off-by: Roman Gilg <subdiff@gmail.com>
Tested-by: Olivier Fourdan <ofourdan@redhat.com>
Clean up only if the request points to the presenting window or its top
parent window.
Since in this case all events are removed unconditionally, always stop
the timer.
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Roman Gilg <subdiff@gmail.com>
This adds initial support for displaying Xwayland applications through
the use of EGLStreams and nvidia's custom wayland protocol by adding
another egl_backend driver. This also adds some additional egl_backend
hooks that are required to make things work properly.
EGLStreams work a lot differently then the traditional way of handling
buffers with wayland. Unfortunately, there are also a LOT of various
pitfalls baked into it's design that need to be explained.
This has a very large and unfortunate implication: direct rendering is,
for the time being at least, impossible to do through EGLStreams. The
main reason being that the EGLStream spec mandates that we lose the
entire color buffer contents with each eglSwapBuffers(), which goes
against X's requirement of not losing data with pixmaps. no way to use
an allocated EGLSurface as the storage for glamor rendering like we do
with GBM, we have to rely on blitting each pixmap to it's respective
EGLSurface producer each frame. In order to pull this off, we add two
different additional egl_backend hooks that GBM opts out of
implementing:
- egl_backend.allow_commits for holding off displaying any EGLStream
backed pixmaps until the point where it's stream is completely
initialized and ready for use
- egl_backend.post_damage for blitting the content of the EGLStream
surface producer before Xwayland actually damages and commits the
wl_surface to the screen.
The other big pitfall here is that using nvidia's wayland-eglstreams
helper library is also not possible for the most part. All of it's API
for creating and destroying streams rely on being able to perform a
roundtrip in order to bring each stream to completion since the wayland
compositor must perform it's job of connecting a consumer to each
EGLstream. Because Xwayland has to potentially handle both responding to
the wayland compositor and it's own X clients, the situation of the
wayland compositor being one of our X clients must be considered. If we
perform a roundtrip with the Wayland compositor, it's possible that the
wayland compositor might currently be connected to us as an X client and
thus hang while both Xwayland and the wayland compositor await responses
from eachother. To avoid this, we work directly with the wayland
protocol and use wl_display_sync() events along with release() events to
set up and destroy EGLStreams asynchronously alongside handling X
clients.
Additionally, since setting up EGLStreams is not an atomic operation we
have to take into consideration the fact that an EGLStream can
potentially be created in response to a window resize, then immediately
deleted due to another pending window resize in the same X client's
pending reqests before Xwayland hits the part of it's event loop where
we read from the wayland compositor. To make this even more painful, we
also have to take into consideration that since EGLStreams are not
atomic that it's possible we could delete wayland resources for an
EGLStream before the compositor even finishes using them and thus run
into errors. So, we use quite a bit of tracking logic to keep EGLStream
objects alive until we know the compositor isn't using them (even if
this means the stream outlives the pixmap it backed).
While the default backend for glamor remains GBM, this patch exists for
users who have had to deal with the reprecussion of their GPU
manufacturers ignoring the advice of upstream and the standardization of
GBM across most major GPU manufacturers. It is not intended to be a
final solution to the GBM debate, but merely a baindaid so our users
don't have to suffer from the consequences of companies avoiding working
upstream. New drivers are strongly encouraged not to use this as a
backend, and use GBM like everyone else. We even spit this out as an
error from Xwayland when using the eglstream backend.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Regardless of the order we un-realize windows.
Suggested-by: Roman Gilg <subdiff@gmail.com>
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Roman Gilg <subdiff@gmail.com>
xwl_unrealize_window() would use freed xwl_window which can lead to
various memory corruption and crashes, as reported by valgrind:
Invalid read of size 8
at 0x42C802: xwl_present_cleanup (xwayland-present.c:84)
by 0x42BA67: xwl_unrealize_window (xwayland.c:601)
by 0x541EE9: compUnrealizeWindow (compwindow.c:285)
by 0x57E1FA: UnrealizeTree (window.c:2816)
by 0x581189: UnmapWindow (window.c:2874)
by 0x54EB26: ProcUnmapWindow (dispatch.c:879)
by 0x554B7D: Dispatch (dispatch.c:479)
by 0x558BE5: dix_main (main.c:276)
by 0x7C4B1BA: (below main) (libc-start.c:308)
Address 0xf520f60 is 96 bytes inside a block of size 184 free'd
at 0x4C2EDAC: free (vg_replace_malloc.c:530)
by 0x42B9FB: xwl_unrealize_window (xwayland.c:624)
by 0x541EE9: compUnrealizeWindow (compwindow.c:285)
by 0x57E1FA: UnrealizeTree (window.c:2816)
by 0x581189: UnmapWindow (window.c:2874)
by 0x54EB26: ProcUnmapWindow (dispatch.c:879)
by 0x554B7D: Dispatch (dispatch.c:479)
by 0x558BE5: dix_main (main.c:276)
by 0x7C4B1BA: (below main) (libc-start.c:308)
Block was alloc'd at
at 0x4C2FB06: calloc (vg_replace_malloc.c:711)
by 0x42B307: xwl_realize_window (xwayland.c:488)
by 0x541E59: compRealizeWindow (compwindow.c:268)
by 0x57DA40: RealizeTree (window.c:2617)
by 0x580B28: MapWindow (window.c:2694)
by 0x54EA2A: ProcMapWindow (dispatch.c:845)
by 0x554B7D: Dispatch (dispatch.c:479)
by 0x558BE5: dix_main (main.c:276)
by 0x7C4B1BA: (below main) (libc-start.c:308)
This is because UnrealizeTree() traverses the tree from top to bottom,
which invalidates the assumption that if the Window doesn't feature an
xwl_window on its own, it's the xwl_window of its first ancestor with
one.
This reverts commit 82df2ce3
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Queue present events to msc values. Fake msc events with a refresh rate of
about 60fps when flips are not possible. When flips are executed rely on
frame callbacks with a slow updating timer as fallback.
This is important for applications, that want to limit their framerate.
Signed-off-by: Roman Gilg <subdiff@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
When the compositor is not sending frame callbacks while we still wait
on buffer release events fake a continuous msc counter with a timer.
Having this timer is a prerequisite for queuing events.
Signed-off-by: Roman Gilg <subdiff@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Introduce support for Present's window flip mode. The support is not yet
complete, but works reasonable well for the most important use case, that
is fullscreen applications.
We take a Present flip and if the xwl_window->window has the same dimensions
as the presenting window, the flip is represented by a wl_buffer and attached
to the main wl_surface of the xwl_window.
After commit we are listening for the sync callback in order to tell Present,
that the pixmap flip is not longer pending, for the frame callback in order
to update the msc counter and for the buffer release callback in order to tell
Present that the pixmap is idle again.
The following functionality is missing from this patch:
* (slowed down) flips in case the compositor is not sending frame callbacks,
* queuing events to MSC times,
* per window flips for child windows with smaller size than the xwl_window.
To make use of this functionality Xwayland must run rootless and with
Glamor/GBM.
Signed-off-by: Roman Gilg <subdiff@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
