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Now the scaler is enabled for the sunxi disp layer only when we want
to use it for YUV format with XV. Whenever the layer is configured
for RGB format or deactivated, the scaler gets disabled.

This should make the driver more friendly to the other potential
scaled layer users. The total number of available scalers is only
2 for Allwinner A10 and only 1 for Allwinner A13.

The potential drawback is that now we may get an error when trying
to enable the scaler (if somebody else has used up all the available
scalers) instead of always having it reserved and ready for use.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Recent changes broke the configuration when "DRI2HWOverlay" option
is set to "false". This patch adds the missing UMP secure ids
initialization and resolves the problem.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Do this to keep the variables naming style consistent across the
source file (earlier these variables had different names like
'self', 'drvpriv', 'private').
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

In double buffer mode, explicitly mark the buffers as designated
for odd or even frame position when putting them into queue. And
when swapping the buffers, use these flags to re-synchronize if
it is necessary. This prevents problems after window resize (when
gles-rgb-cycle-demo could expose a mismatch between the color
name in the window title and the actual window color).
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Whenever something goes wrong in high fps mode, it may be interesting
to slow down the demo to check whether the actual background color
matches the expected color (shown in the window title).
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

If DEBUG_WITH_RGB_PATTERN is defined, then we check that the
frames colors are changed as "R -> G -> B -> R -> G -> ..."
pattern and print debugging messages when this is not the
case. Such color change pattern can be generated by the
"test/gles-rgb-cycle-demo.c" program.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Do this mostly for security reasons. We don't want any application
to see whatever was last rendered by the previous GLES application
by just peeking into a freshly allocated DRI2 buffer.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

We manage only a single hardware overlay. That's a precious shared
resource, which we want to use for zero-copy fullscreen compositing
in gnome-shell. The strange 1x1 window does not really need it.
Fixes https://github.com/ssvb/xf86-video-sunxifb/issues/2

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

When enabled, it tries to avoid tearing in OpenGL ES applications.
Works on sunxi hardware in the case if the hardware overlay (sunxi
disp layer) is used for a DRI2 window. The name of this option and
the description in the man page has been borrowed from intel and
radeon drivers.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

That's the right thing to do and fixes issues such as
    https://github.com/ssvb/xf86-video-sunxifb/issues/6



As a result, now the framebuffer size may need to be larger in
order to accomodate two DRI2 buffers in the offscreen part of
the framebuffer. The users of sunxi hardware are advised to
increase the value of fb0_framebuffer_num variable in fex file
to 3 for 32bpp mode and to 5 for 16bpp mode.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Should fix https://github.com/ssvb/xf86-video-sunxifb/issues/14


and prevent FTBFS on some systems.
Reported-by: Fred Chien <cfsghost@gmail.com>
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

When moving further to our own DRI2 buffers bookkeeping, we can't
really trust the information from DRI2BufferRec anymore. So just add
a copy of all the missing bits of information to UMPBufferInfoRec
and use it instead.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

By allowing to set the delay between frames with milliseconds
precision in the command line, we can use it to test vsync.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

The recent commit 9e0a8731

 (its part
that suppressed buffers reuse in the Xorg DRI2 framework) introduced
a regression. Half of the frames stoppped reaching the screen on
the CPU copy fallback path because the Mali blob now ended up
rendering them to the "wrong" buffer.

It just confirms that we need to completely move from the standard
DRI2 framework in the Xorg server to our own buffers bookkeeping
logic. This patch fixes the regression by introducing a single UMP
buffer per window, which is shared between back and front DRI2
buffers. We can do this because double buffering does not make much
sense on the fallback path at the moment (we can't set scanout from
this buffer and anyway have to copy this data elsewhere immediately
after we get it from Mali).
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Bail out earlier for the uninteresting types of DRI2 buffer
requests (by just returning a dummy null UMP buffer). Makes
the code a bit more simple on the common path.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

The test program cycles through 3 colors (red, green, blue), so
it is easier to see if we get the color change pattern wrong.
Also the X11 window title is updated to indicate the current
color information. If we have any problems with window
decorations handling, they are likely to be exposed.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Using the secure id 1 (framebuffer) to trick the Mali blob into
requesting DRI2 buffers again was not a very good idea. The problem
is that the blob still writes something there and corrupts the
framebuffer. So instead we try to assign secure id 2 to a dummy
4KiB UMP buffer allocated in memory and use it for the same purpose.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

The Mali blob is doing something like this:

 1. Request BackLeft DRI2 buffer (buffer A) and render to it
 2. Swap buffers
 3. Request BackLeft DRI2 buffer (buffer B)
 4. Check window size, and if it has changed - go back to step 1.
 5. Render to the current back buffer (either buffer A or B)
 6. Swap buffers
 7. Go back to step 4

A very serious show stopper problem is that the Mali blob ignores
DRI2-InvalidateBuffers events and just uses GetGeometry polling
to check whether the window size has changed. Unfortunately this
is racy and we may end up with a size mismatch between buffer A
and buffer B. This is particularly easy to trigger when the window
size changes exactly between steps 1 and 3.

See test/gles-yellow-blue-flip.c program which demonstrates this.
Qt5 applications also trigger this bug.

We workaround the issue by explicitly tracking the requests for
BackLeft buffers and checking whether the sizes of these buffers
match at step 1 and step 3. However the real challenge here is
notifying the client application that these buffers are no good,
so that it can request them again. As DRI2-InvalidateBuffers
events are ignored, we are in a pretty difficult situation.
Fortunately I remembered a weird behaviour observed earlier:

    https://groups.google.com/forum/#!msg/linux-sunxi/qnxpVaqp1Ys/aVTq09DVih0J



Actually if we return UMP secure ID value 1 for the second DRI2
buffer request, the blob responds to this by spitting out the
following error message:

    [EGL-X11] [2274] DETECTED ONLY ONE FRAMEBUFFER - FORCING A RESIZE
    [EGL-X11] [2274] DRI2 UMP ID 0x3 retrieved
    [EGL-X11] [2274] DRI2 WINDOW UMP SECURE ID CHANGED (0x3 -> 0x3)

And then it proceeds by re-trying to request a pair of DRI2 buffers.
But that's exactly the behaviour we want! As a down side, some ugly
flashing can be seen on screen at the time when this workaround kicks
in, but then everything normalizes. And unfortunately, the race
condition is still not totally eliminated because the blob is
apparently getting DRI2 buffer sizes from the separate GetGeometry
requests instead of using the information provided by DRI2GetBuffers.
But now the problem is at least very hard to trigger.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Since version 1.0, gstreamer (when using xvimagesink) often
allocates a larger XV image for the video with padding on all
four sides and then calls XvPutImage() to render a part of this
image. With the current XV implementation this results in
artifacts on the borders of the image, with a green bar at the
bottom.

I am observing this when playing a 1280x720 video on a 1920x1080
screen at 32bpp, the size of the video window doesn't matter.

This problem seems to be an exaggeration of the one described in
https://bugzilla.gnome.org/show_bug.cgi?id=685305

.

The solution appears to be to use the source area dimensions as
requested in the XvPutImage() call, as opposed to the dimensions
of the originally allocated image, and to honour the offsets
(src_x, src_y) when setting the source region on the display
controller. With this relatively simple change, the problem seems
to go away, and gstreamer 1.0 (which is faster than gstreamer 0.10
due to a zero-copy strategy) provides an acceptable solution for
video playback.
Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>

In the case if an attempt to reserve a scalable sunxi-disp layer
failed, don't initialize XV at all. Otherwise any attempt to use
XV overlay is not going to work correctly and just results in
the following dmesg spam:

[  728.280000] [DISP] not supported yuv channel format:18 in img_sw_para_to_reg

This may happen on Allwinner A13 if scaler mode is enabled in
.fex file (A13 only has one DEFE scaler). Allwinner A10 also
can have similar troubles in dual-head configuration if scaler
mode is enabled for one or both screens (A10 has two DEFE scalers).
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Update the man page and bring it up-to-date, reflecting the fact
that the driver also supports non-sunxi platforms. Add description
of the "XVHWOverlay" option.

Also a small update to the README for similar reasons.
Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>

Add the "XVHWOverlay" boolean xorg.conf option to make it possible
to disable the XV acceleration feature using display layers on
sunxi hardware.
Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>

In some systems libump library is built without an explicit pthreads
dependency. As the issue has been already confirmed to affect both
sunxi and odroid users (and maybe the users of the other mali400
based hardware), it is easier to just workaround the problem locally.
Otherwise we would need to hunt down all the libump packagers and
beg for the fix.

More details are at https://github.com/ssvb/xf86-video-sunxifb/issues/11



Reported-by: Patrick Wood
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Proper layer sharing between XV and DRI2 still needs to be implemented.
Additionally we still need NEON and/or G2D "textured overlay" as a
fallback solution for the composited desktop (NEON optimized XV is going
to be useful for a wide range of ARM devices). A bit of performance
tuning is also necessary.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

They are needed for a basic XV extension implementation.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Benchmark tests reveal that xorg's fb layer PutImage implementation
does not follow on optimal code path for requests without special
raster operations, which is due to the use of a slower general blit
function instead of the pixman library. This affects Xlib PutImage
requests and some ShmPutImage requests. In the case of ShmPutImage,
xorg directs ShmPutImage requests to PutImage only if the width of
the part of the image to be copied is equal to the full width of
the image, resulting in relatively poor performance. If the width
of the part of the image that is copied is smaller than the full
image, then xorg uses CopyArea which results in the use of the
already optimal pixman blit functions. The sub-optimal path is
commonly triggered by applications such as window managers and web
browsers.

To fix this unnecessary performance flaw, PutImage is replaced with
a version that uses pixman for the common case of GXcopy and all
plane masks sets. This change is device-independent and only uses
pixman CPU blit functions that is already present in the xorg server.

Using the low-level benchmark program benchx
(https://github.com/hglm/benchx.git

), the following speed-ups were
measured (1920x1080x32bpp) on an Allwinner A10 device:

ShmPutImageFullWidth (5 x 5): Speed up 9%
ShmPutImageFullWidth (7 x 7): Slow down 5%
ShmPutImageFullWidth (22 x 22): Speed up 8%
ShmPutImageFullWidth (49 x 49): Speed up 19%
ShmPutImageFullWidth (73 x 73): Speed up 55%
ShmPutImageFullWidth (109 x 109): Speed up 50%
ShmPutImageFullWidth (163 x 163): Speed up 37%
ShmPutImageFullWidth (244 x 244): Speed up 111%
ShmPutImageFullWidth (366 x 366): Speed up 77%
ShmPutImageFullWidth (549 x 549): Speed up 92%
AlignedShmPutImageFullWidth (5 x 5): Slow down 14%
AlignedShmPutImageFullWidth (7 x 7): Slow down 6%
AlignedShmPutImageFullWidth (15 x 15): Speed up 10%
AlignedShmPutImageFullWidth (22 x 22): Speed up 9%
AlignedShmPutImageFullWidth (33 x 33): Speed up 21%
AlignedShmPutImageFullWidth (49 x 49): Speed up 28%
AlignedShmPutImageFullWidth (73 x 73): Speed up 30%
AlignedShmPutImageFullWidth (109 x 109): Speed up 47%
AlignedShmPutImageFullWidth (163 x 163): Speed up 38%
AlignedShmPutImageFullWidth (244 x 244): Speed up 63%
AlignedShmPutImageFullWidth (366 x 366): Speed up 84%
AlignedShmPutImageFullWidth (549 x 549): Speed up 89%

At 16bpp the speed-up is even greater:

ShmPutImageFullWidth (5 x 5): Slow down 8%
ShmPutImageFullWidth (7 x 7): Slow down 8%
ShmPutImageFullWidth (10 x 10): Slow down 6%
ShmPutImageFullWidth (22 x 22): Speed up 9%
ShmPutImageFullWidth (33 x 33): Speed up 20%
ShmPutImageFullWidth (49 x 49): Speed up 27%
ShmPutImageFullWidth (73 x 73): Speed up 69%
ShmPutImageFullWidth (109 x 109): Speed up 74%
ShmPutImageFullWidth (163 x 163): Speed up 100%
ShmPutImageFullWidth (244 x 244): Speed up 111%
ShmPutImageFullWidth (366 x 366): Speed up 133%
ShmPutImageFullWidth (549 x 549): Speed up 123%
AlignedShmPutImageFullWidth (5 x 5): Speed up 6%
AlignedShmPutImageFullWidth (7 x 7): Slow down 9%
AlignedShmPutImageFullWidth (10 x 10): Slow down 10%
AlignedShmPutImageFullWidth (33 x 33): Speed up 17%
AlignedShmPutImageFullWidth (49 x 49): Speed up 34%
AlignedShmPutImageFullWidth (73 x 73): Speed up 49%
AlignedShmPutImageFullWidth (109 x 109): Speed up 53%
AlignedShmPutImageFullWidth (163 x 163): Speed up 69%
AlignedShmPutImageFullWidth (244 x 244): Speed up 82%
AlignedShmPutImageFullWidth (366 x 366): Speed up 116%
AlignedShmPutImageFullWidth (549 x 549): Speed up 110%
Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>

This should be useful for Raspberry Pi. When reading uncached source buffers,
the VFP optimized overlapped two-pass blit is roughly 2-3 times slower than
memcpy in cached memory. Which makes it reasonably competitive compared to
ShadowFB (considering that ShadowFB allocates an extra buffer, does extra
memory copies which take time and thrash L2 cache, etc.). It even provides
a slight performance advantage in a more or less realistic use case
(scrolling in xterm), which needs reads from the framebuffer:

==== Before (xf86-video-fbdev with ShadowFB) ====

$ time DISPLAY=:0 xterm +j -maximized -e cat longtext.txt

real    1m50.245s
user    0m1.750s
sys     0m0.800s

==== After (xf86-video-sunxifb without ShadowFB) ====

$ time DISPLAY=:0 xterm +j -maximized -e cat longtext.txt

real    1m27.709s
user    0m1.690s
sys     0m0.920s

We get decent results even when reading from the framebuffer. However
in many typical workloads (excluding scrolling and dragging windows)
the framebuffer is primarily used as write-only. In write-only use
cases ShadowFB is just pure overhead. So getting rid of it is a
very good idea as this improves overall graphics performance.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

A small typo in a function argument and C compiler happily accepting
void pointers instead of something else is a dangerous combo. Need to
be more careful.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

This patch implements a heuristics, which enables backing store for some
windows. When backing store is enabled for a window, the window gets a
backing pixmap (via automatic redirection provided by composite extension).
It acts a bit similar to ShadowFB, but for individual windows.

The advantage of backing store is that we can avoid "expose event -> redraw"
animated trail in the exposed area when dragging another window on top of it.
Dragging windows becomes much smoother and faster.

But the disadvantage of backing store is the same as for ShadowFB. That's a
loss of precious RAM, extra buffer copy when somebody tries to update window
content, potentially skip of some frames on fast animation (they just do
not reach screen). Also hardware accelerated scrolling does not currently
work for the windows with backing store enabled.

We try to make the best use of backing store by enabling backing store for
all the windows that are direct children of root, except the one which has
keyboard focus (either directly or via one of its children). In practice this
heuristics seems to provide nearly perfect results:
 1) dragging windows is fast and smooth.
 2) the top level window with the keyboard focus (typically the application
    that a user is working with) is G2D accelerated and does not suffer from
    any intermediate buffer copy overhead.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

With the fallback to CPU backend for unsupported blits and also
threshold for avoiding small blits, now G2D should always provide
best overall performance.

The users of recent versions of xf86-video-sunxifb are supposed
to also have a reasonably recent version of linux-sunxi kernel.
Which includes the following fix:
  https://github.com/linux-sunxi/linux-sunxi/commit/3d49345343a1535b



The users of old kernels are going to see screen corruption on
dragging windows and scrolling. They just should upgrade :)
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

The G2D driver only supports framebuffer->framebuffer blits and
also can't be used to accelerate dragging windows to the right
(without hacking the kernel driver to do two-pass blit there).
This patch adds fallback to NEON optimized CPU backend instead
of resorting to use poorly performing fbBlt in these cases.

Note: we assume that ioctls normally do not fail (even if they
      do, the slow old style fallback to fbBlt is not the worst
      thing to worry about).
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Using VFP, we can load up to 128 bytes with a single VLDM instruction.
But before this patch, only NEON implementation was available. Just
because it showed better results on Allwinner A10 compared to VFP.
And this DDX driver used to primarily target just sunxi hardware.

But looks like it makes sense to also target other devices (at least
ODROID-X, which has the same Mali400 GPU and can use the same DRI2
integration for EGL and GLESv2 support). And on the other ARM devices,
VFP aligned reads generally work better than NEON. The benchmark
results are listed below:

            1280x720, 32bpp, testing "x11perf -scroll500"

== Exynos 5250, Cortex-A15, Non-cacheable streaming enhancement disabled ==

NEON : 10000 trep @   3.7101 msec (   270.0/sec): Scroll 500x500 pixels
VFP  : 10000 trep @   2.6678 msec (   375.0/sec): Scroll 500x500 pixels

== Exynos 5250, Cortex-A15, Non-cacheable streaming enhancement enabled ==

NEON : 15000 trep @   2.2568 msec (   443.0/sec): Scroll 500x500 pixels
VFP  : 15000 trep @   2.3016 msec (   434.0/sec): Scroll 500x500 pixels

== Exynos 4412, Cortex-A9 ==

NEON : 10000 trep @   4.5125 msec (   222.0/sec): Scroll 500x500 pixels
VFP  : 10000 trep @   2.7015 msec (   370.0/sec): Scroll 500x500 pixels

== TI DM3730, Cortex-A8 ==

NEON : 15000 trep @   2.2303 msec (   448.0/sec): Scroll 500x500 pixels
VFP  : 10000 trep @   3.0670 msec (   326.0/sec): Scroll 500x500 pixels

== Allwinner A10, Cortex-A8 ==

NEON : 10000 trep @   2.5559 msec (   391.0/sec): Scroll 500x500 pixels
VFP  : 10000 trep @   3.0580 msec (   327.0/sec): Scroll 500x500 pixels

== Raspberry Pi, BCM2708, ARM1176 ==

VFP  :  3000 trep @   8.7699 msec (   114.0/sec): Scroll 500x500 pixels

The benchmark numbers in this particular test setup roughly represent
memory copy bandwidth measured in MB/s (when doing overlapped blits
inside of a writecombine mapped framebuffer).

-----------------------------------------------------------------------

Note: the use of VFP two-pass overlapped copy instead of ShadowFB is
      still not enabled by default when running on Raspberry Pi
      because the performance results are not so great.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

This is my old ARM9E/ARM11 memcpy code from
    https://garage.maemo.org/projects/mplayer/


with some tuning for Raspberry Pi (aligned prefetch added).

Will be used by VFP optimized overlapped blt function.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

When source and destination coordinates allow it, a 16bpp screen-to-
screen blit is divided into up to three segments: two optional one
pixel wide edges and an  aligned middle segment that is copied in
32-bit mode.

This patch adds the low-level function sunxi_g2d_blit_r5g6b5_in_three
and adds logic to the general blit function to use it for 16bpp to
16bpp blits if the source and destination coordinates allow it. This
patch automatically enables the use of this optimization in the
sunxi G2D X driver. The area threshold for using G2D for
16bpp-to-16bpp blits was introduced in a previous patch.

Benchmarks:

1920x1080x16bpp@60Hz, ShadowFB disabled:

x11perf -scroll100
Before:
 350000 trep @   0.0881 msec ( 11400.0/sec): Scroll 100x100 pixels
After:
 350000 trep @   0.0819 msec ( 12200.0/sec): Scroll 100x100 pixels

x11perf -scroll500
Before:
  20000 trep @   1.3547 msec (   738.0/sec): Scroll 500x500 pixels
After:
  35000 trep @   0.8005 msec (  1250.0/sec): Scroll 500x500 pixels
Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>

Due to the overhead of G2D for small screen-to-screen blits, CPU blits
are faster for small areas. This patch introduces are threshold below
which CPU blits are triggered. It is currently set to 1000 for 32bpp
and 2500 for 16bpp based on test results.

Some benchmarks:

1920x1080x16bppx60Hz, ShadowFB disabled:

x11perf -scroll10

Before:
1500000 trep @   0.0239 msec ( 41800.0/sec): Scroll 10x10 pixels
After:
2500000 trep @   0.0110 msec ( 90900.0/sec): Scroll 10x10 pixels

x11perf -copywinwin10

Before:
1200000 trep @   0.0247 msec ( 40500.0/sec): Copy 10x10 from window to window
After:
1800000 trep @   0.0146 msec ( 68600.0/sec): Copy 10x10 from window to window
Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>

This test program exposes a problem related to window resizing
(or going fullscreen), which is may happen exactly between "back"
and "front" DRI2 buffers allocation.

The xtrace log with some annotations:

000:<:004c:  8: DRI2-Request(151,3): CreateDrawable drawable=0x02200001
000:<:004d: 16: DRI2-Request(151,5): GetBuffers drawable=0x02200001 attachments={attachment=BackLeft(0x00000001)};
000:>:004d:52: Reply to GetBuffers: width=480 height=480 buffers={attachment=BackLeft(0x00000001)
                                    name=0x00000157 pitch=1920 cpp=4 flags=0x00000000};

Get the BackLeft buffer.

000:<:004e:  4: Request(43): GetInputFocus
000:>:004e:32: Reply to GetInputFocus: revert-to=PointerRoot(0x01) focus=0x02200001
000:<:004f: 24: Request(16): InternAtom only-if-exists=false(0x00) name='_NET_WM_STATE'
000:>:004f:32: Reply to InternAtom: atom=0xff("_NET_WM_STATE")
000:<:0050: 32: Request(16): InternAtom only-if-exists=false(0x00) name='_NET_WM_STATE_FULLSCREEN'
000:>:0050:32: Reply to InternAtom: atom=0x102("_NET_WM_STATE_FULLSCREEN")
000:<:0051: 44: Request(25): SendEvent propagate=false(0x00) destination=0x00000170 event-mask=SubstructureNotify,SubstructureRedirect
                             ClientMessage(33) format=0x20 window=0x02200001 type=0xff("_NET_WM_STATE")
                             data=0x01,0x00,0x00,0x00,0x02,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00;
000:<:0052:  4: Request(43): GetInputFocus
000:>:0052: Event DRI2-InvalidateBuffers(102) drawable=0x02200001

Here the X server attempts to notify the client side DRI2 code in the Mali blob
that the DRI2 buffer must be requested again. But this event gets happily ignored.

000:>:0052: Event Expose(12) window=0x02200001 x=0 y=0 width=1920 height=1080 count=0x0000
000:>:0052:32: Reply to GetInputFocus: revert-to=PointerRoot(0x01) focus=0x02200001
000:<:0053:  8: Request(3): GetWindowAttributes window=0x02200001
000:<:0054:  8: Request(14): GetGeometry drawable=0x02200001
000:>:0053:44: Reply to GetWindowAttributes: backing-store=NotUseful(0x00) visual=0x00000021 class=InputOutput(0x0001)
                                             bit-gravity=Forget(0x00) win-gravity=NorthWest(0x01) backing-planes=0xffffffff
                                             backing-pixel=0x00000000 save-under=false(0x00) map-is-installed=true(0x01)
                                             map-state=Viewable(0x02) override-redirect=false(0x00) colormap=0x00000020
                                             all-event-masks=PointerMotion,Exposure,StructureNotify,FocusChange,PropertyChange
                                             your-event-mask=PointerMotion,Exposure do-not-propagate-mask=0 unused=0x0000
000:>:0054:32: Reply to GetGeometry: depth=0x18 root=0x00000170 x=0 y=0 width=1920 height=1080 border-width=0
001:<:000c: 12: Request(98): QueryExtension name='DRI2'
001:>:000c:32: Reply to QueryExtension: present=true(0x01) major-opcode=151 first-event=101 first-error=0
001:<:000d: 32: DRI2-Request(151,8): SwapBuffers drawable=0x02200001 target_msc_hi=0 target_msc_lo=0
                                     divisor_hi=0 divisor_lo=0 remainder_hi=0 remainder_lo=0
001:>:000d: Event DRI2-BufferSwapComplete(101) drawable=0x00000002 ust_hi=35651585 ust_lo=0 msc_hi=0 msc_lo=0 sbc_hi=0 sbc_lo=1

Here the DRI2 code from the Mali blob tries to swap buffers (with the
hope that the allocated BackLeft would go to front)

001:>:000d:32: Reply to SwapBuffers: swap_hi=0 swap_lo=4096
000:<:0055:  8: DRI2-Request(151,3): CreateDrawable drawable=0x02200001
000:<:0056: 16: DRI2-Request(151,5): GetBuffers drawable=0x02200001 attachments={attachment=BackLeft(0x00000001)};
000:>:0056:52: Reply to GetBuffers: width=1920 height=1080 buffers={attachment=BackLeft(0x00000001)
                                    name=0x00000159 pitch=7680 cpp=4 flags=0x00000000};

And requests for the new BackLeft DRI2 buffer.

000:<:0057:  4: Request(43): GetInputFocus
000:>:0057:32: Reply to GetInputFocus: revert-to=PointerRoot(0x01) focus=0x02200001
000:<:0058:  8: Request(3): GetWindowAttributes window=0x02200001
000:<:0059:  8: Request(14): GetGeometry drawable=0x02200001
000:>:0058:44: Reply to GetWindowAttributes: backing-store=NotUseful(0x00) visual=0x00000021 class=InputOutput(0x0001)
                                             bit-gravity=Forget(0x00) win-gravity=NorthWest(0x01) backing-planes=0xffffffff
                                             backing-pixel=0x00000000 save-under=false(0x00) map-is-installed=true(0x01)
                                             map-state=Viewable(0x02) override-redirect=false(0x00) colormap=0x00000020
                                             all-event-masks=PointerMotion,Exposure,StructureNotify,FocusChange,PropertyChange
                                             your-event-mask=PointerMotion,Exposure do-not-propagate-mask=0 unused=0x0000
000:>:0059:32: Reply to GetGeometry: depth=0x18 root=0x00000170 x=0 y=0 width=1920 height=1080 border-width=0
000:<:005a:  8: Request(3): GetWindowAttributes window=0x02200001
000:<:005b:  8: Request(14): GetGeometry drawable=0x02200001
000:>:005a:44: Reply to GetWindowAttributes: backing-store=NotUseful(0x00) visual=0x00000021 class=InputOutput(0x0001)
                                             bit-gravity=Forget(0x00) win-gravity=NorthWest(0x01) backing-planes=0xffffffff
                                             backing-pixel=0x00000000 save-under=false(0x00) map-is-installed=true(0x01)
                                             map-state=Viewable(0x02) override-redirect=false(0x00) colormap=0x00000020
                                             all-event-masks=PointerMotion,Exposure,StructureNotify,FocusChange,PropertyChange
                                             your-event-mask=PointerMotion,Exposure do-not-propagate-mask=0 unused=0x0000
000:>:005b:32: Reply to GetGeometry: depth=0x18 root=0x00000170 x=0 y=0 width=1920 height=1080 border-width=0
001:<:000e: 32: DRI2-Request(151,8): SwapBuffers drawable=0x02200001 target_msc_hi=0 target_msc_lo=0
                                     divisor_hi=0 divisor_lo=0 remainder_hi=0 remainder_lo=0
001:>:000e: Event DRI2-BufferSwapComplete(101) drawable=0x00000002 ust_hi=35651585 ust_lo=0 msc_hi=0 msc_lo=0 sbc_hi=0 sbc_lo=2

And here it is simply swapping the buffers.

001:>:000e:32: Reply to SwapBuffers: swap_hi=0 swap_lo=4096
000:<:005c:  8: Request(3): GetWindowAttributes window=0x02200001
000:<:005d:  8: Request(14): GetGeometry drawable=0x02200001
000:>:005c:44: Reply to GetWindowAttributes: backing-store=NotUseful(0x00) visual=0x00000021 class=InputOutput(0x0001)
                                             bit-gravity=Forget(0x00) win-gravity=NorthWest(0x01) backing-planes=0xffffffff
                                             backing-pixel=0x00000000 save-under=false(0x00) map-is-installed=true(0x01)
                                             map-state=Viewable(0x02) override-redirect=false(0x00) colormap=0x00000020
                                             all-event-masks=PointerMotion,Exposure,StructureNotify,FocusChange,PropertyChange
                                             your-event-mask=PointerMotion,Exposure do-not-propagate-mask=0 unused=0x0000
000:>:005d:32: Reply to GetGeometry: depth=0x18 root=0x00000170 x=0 y=0 width=1920 height=1080 border-width=0

And now it is polling for the change of window geometry. The same
"SwapBuffers -> GetGeometry -> SwapBuffers" pattern keeps repeating.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Should be useful for better performance when moving windows
and scrolling on the devices without a dedicated 2D hardware
accelerator (Allwinner A13).
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

Just use "/dev/fb0" by default.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>