Sharp's tc6393fb.h has enough information to experiment. First, I'd try modifying the fill command to draw colored boxes on the screen. This is very useful for accelerating window managers, as they tend to draw the backing color, then the objects on top. The source copy would be great for moving windows, scrolling windows, scrolling the console, and drawing console characters.
The TC6393 has 1MB of video memory. The default 640x480x16bit mode only uses 600kB, leaving 424kB for console fonts, bitmaps, etc, for source copy. Also, 424kB is enough for one large 528x400 buffer. With a custom mplayer plugin, mplayer can render to that off-screen buffer, then StretchBLT the buffer to the 640x480 screen. It looks like StretchBLT has vertical reverse and horizontal reverse options, too, so you can flip horizontal, or flip vertical, or rotate the video 180 degrees in hardware.
I'm working on the 2.6 kernel at the moment, and I'll work on video acceleration at some point (it's a low priority, so it could be a while). If someone wants to experiment and help out, that'd be even better. =)
The TC6393's LCD controller has five accelration commands:
PXAIO_COMDI_CMGO - Cursor Move?
PXAIO_COMDI_FLGO - Fill
PXAIO_COMDI_SCGO - Source Copy
PXAIO_COMDI_SBGO - StretchBLT
PXAIO_COMDI_LDGO - Line Draw
Out of the set commands, we can group by ones that take a pixel color as a paremeter:
PXAIO_COMDI_FILL - fill color
PXAIO_COMDI_TCLOR - transparent color for Source Copy
ones that take a memory address as a parameter:
PXAIO_COMDI_CSADR - cursor screen address?
PXAIO_COMDI_PSADR - physical screen address?
PXAIO_COMDI_POADR - physical offset address?
PXAIO_COMDI_DSADR - destination screen address?
PXAIO_COMDI_SSADR - source screen address?
and ones that take a x or y offset or pixel count as a parameter:
PXAIO_COMDI_CHPIX - cursor horizontal pixels?
PXAIO_COMDI_CVPIX - cursor vertical pixels?
PXAIO_COMDI_PHPIX - physical horizontal pixels?
PXAIO_COMDI_PVPIX - physical vertical pixels?
PXAIO_COMDI_PHOFS - physical horizontal offset?
PXAIO_COMDI_PVOFS - physical vertical offset?
PXAIO_COMDI_DHPIX - destination horizontal pixels
PXAIO_COMDI_DVPIX - destination vertical pixels
PXAIO_COMDI_SHPIX - source horizontal pixels?
PXAIO_COMDI_SVPIX - source vertical pixels?
