[Freedreno] Freedreno: EXA acceleration?

[Pallai Roland]

2014/1/24 Rob Clark <robdclark at gmail.com>:
> On Thu, Jan 23, 2014 at 9:05 PM, Pallai Roland <pallair at magex.hu> wrote:
>
> Currently all EXA falls back to software.  But it is enough for dri2
> to work (so 3d stuff, including gl compositing window managers will be
> accelerated.
> [...]
> Last time I had XA working, it didn't seem like a huge performance
> win.  Although I suppose it should benefit from at least some of the
> improvements in freedreno gallium since then.  But a tiler gpu in
> particular is not really terribly ideal for lots of small EXA
> composite ops (font rendering, etc).  At least we can bypass tiling
> for solid fills and blits (so it will at least be good for
> presentation blits for windowed 3d apps).
> [...]
>> My hobby project is a portable thin client mainly for ssh/spice
>> sessions with fast and fluent window management on multiple
>> workspaces. Seems like EXA is an important thing for that, now
>> scrolling and anti-aliased font rendering in the terminal is pretty
>> slow.
> Probably adding support for cached GEM buffers might help out some
> cases.  For small composite ops (like font rendering), I don't think
> the GPU will outperform the CPU.

My problem with slow 2D rendering came from text rendering over
XRender. I did some measuring with Qperf and found Qt text rendering
on client side 10 times faster than XRender (measured with
QT_GRAPHICSSYSTEM={native,raster}). I disabled XRender in Firefox,
changed Gnome-terminal to Konsole and the experience is much better
now.

I agree, seems like EXA in a modern desktop environment is not so
critical. Qt does not use XRender/EXA from 4.8 by default, Qt5 even
dropped the support. I'm running Kwin (KDE) in OpenGL 1.2
compatibility mode, my desktop works like a charm!
It's interesting that moving of the windows much faster in Kwin than
in Gnome3 - maybe the javascript is slow there..?


I've one more question about your HDMI resolutions for you since I've
seen your 1024x768 support patch;
I'd like to drive my monitor in native resolution 1280x1024p60
(108Mhz) but the documentation isn't too chatty on programming of HDMI
PLL registers, do you have some extra info?
I've opened a ticket at inforcecomputing, but no reply, yet.


Thanks for your help!