Hello,
On Mon, Mar 31, 2014 at 11:49 AM, Dr. H. Nikolaus Schaller hns@goldelico.com wrote:
Am 30.03.2014 um 23:50 schrieb Grazvydas Ignotas:
On 03/31/2014 12:26 AM, Dr. H. Nikolaus Schaller wrote:
Unless the TILER is set up in kernel and invisible to user space. I am not yet convinced that this is impossible.
For X apps it can be invisible since xf86-whatever driver does the buffer setup, but there is always extra copying involved for app to display something on screen through X, and that is slow.
For direct access it can't be invisible without extra overhead for hidden copies, because of the page format that TILER needs. However it's possible express something that matches TILER's page format in things like SDL and programs that don't assume linear buffer will work.
I'd say right now the main issues now are slowness and read failures; I could only reach 16fps for fullhd drawing while rotated, which is way below 60fps.
But we won't get full hd rotated with the extra chip either (because it can't handle that resolution).
Perhaps we should not use fullhd screen then?
Without rotation same code can do over 130fps..
Which the display can't even handle...
This just shows that updating fullhd screen @60fps normally takes around half of processing power that CortexA15 has, this is quite a lot already. If we did some processing (alpha blending?), the CPU likely wouldn't be able to keep up at all.
With rotation, it would need ~4x more of something (better TILER response, better memory controller latency, less errors?) than current hw+sw setup we have to be able to update the screen @60fps.
We need to be able to at least update the whole screen at it's refresh rate and have a bit of CPU time left. If this can't be achieved, the setup is unacceptable IMO. I'd say having to use half of CPU time for 60Hz (in unrotated mode) is already bad enough and really limits things you can do..
GraÅžvydas