Fwd: LCM flicker

[Carsten Haitzler (The Rasterman)]

On Sat, 8 Mar 2008 15:33:36 -0500 "Kyle Bassett" <kylebassett at gmail.com>
babbled:

for now i think we need to live with flicker. we can work around this in
xglamo. we can pull the shadow-buffer trick. put the working frontbuffer fb in
offscreen video memory, keep a pipeline queue of update regions, then on
pipeline flush merge the rects and copy them from the shadowbuffer to
the real "on-screen" framebuffer. the 2d engine on the glamo supports rotated
blits by multiples of 90 degrees as well as mirroring, so this can be handled
by the hardware.

we'd pay an overhead price for this, but the cost would be glamo-side, not
cpu-side. it wouldn't affect our glamo interconnect bandwidth etc.

the other option is to make all gfx ops rotate/flip aware and use the modes in
2d to do everything natively at the rotated mode. any software fallbacks then
need to be coded to work in rotated mode too. this would man no (big)
performance hit (software may due to different cacheline accesses - but i'll
ignore for now), but would be a fair bit more work.

imho - this is something that, i u can't get the lcm to behave right in rotated
mode and not flicker, punt it off to the glamo engine to handle later on (we
probably would punt this to the end of the list of things to do 2d-wise).

> Maybe Tony can work his magic with the LCM manufacturer. ;-)
> 
> -Kyle
> 
> 
> On Sat, Mar 8, 2008 at 8:25 AM, Andy Green <andy at openmoko.com> wrote:
> 
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > Somebody in the thread at some point said:
> >
> > > We need a bit more information about the internal structure of the LCM.
> >
> > If anyone is interested to get a little more data about the LCM free of
> > NDA, Google tells us you can find a large chunk of what we are working
> > from here (shown with wget due to embedded spaces in URL):
> >
> > wget -O /tmp/lcm.pdf
> > "
> > http://www.beck-oled-lcd-tft-display.de/display-datenblatt/typ/tpo/TD028TTEC1
> > Product Spec Ver1.2 .pdf"
> >
> > - -Andy
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> 


-- 
Carsten Haitzler (The Rasterman) <raster at openmoko.org>