OESF Portables Forum
General Forums => General Discussion => Topic started by: danboid on October 04, 2006, 03:54:25 am
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http://sourceforge.net/mailarchive/forum.p...&forum_id=11924 (http://sourceforge.net/mailarchive/forum.php?thread_id=30632812&forum_id=11924)
Follow the above link for Hrw's announcement of the new kernel which now supports QVGA res, overlay and SRAM on pxa270 devices! I want to say thanks to RP, Hrw and all the other OZ devs for getting this out the door.
It needs testing ataik but IMO this was the single biggest missing feature from the OZ 2.6 kernel stopping cacko/sharp users from making the switch so I'm posting here to make sure the maximum amount of Z users and devs are aware of it so we can hopefully get this off the ground sooner.
The problem now is that no software in OZ takes advantage of these new features. I should imagine that the X server, SDL and mplayer will all require patches before we see the full benefits of this.
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kernel which now supports QVGA res, overlay and SRAM on pxa270 devices!
[div align=\"right\"][a href=\"index.php?act=findpost&pid=143030\"][{POST_SNAPBACK}][/a][/div]
AFAIK it has no SRAM support yet.
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Oh well- soon soon soon!
Thanks for letting me know k
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YEAH!!!!!!
this is truley incredable, i belive its time for me to set my Z up properly now
anyway back on topic, how much of an advantage would SRAM be, would we be using it for the frame buffer, because at 640x480 the frame is larger than the sram.
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Da Blitz:
Yeah, I think I've heard that before (about SRAM not being sufficient for 640x480) such a shame
Still, as long as we could use the SRAM in QVGA mode it will be ideal for all the emulators, most of which don't need a higher res than 320x240.
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actually it is still handy as if it is used for part of the framebuffer then you would see a performance incrsses for that part, however you would need the base address for the sram to be someewhere in SDRAM so that the rest of the pixels arent mapped to a bit bucket in the sky.
basically it means you dont hammer the SDRAM all the ttime and with 16 bit at 6440x480, thats a large part of the mem bandwidth gone, intel even has a data sheet detailing its effects and how to calculate the bandwidth used
if i remeber correctly its 640 * 480 * 2 * 30 (hieght, width, Bytes per pixel, framerate) = 17MB/s
SDRAM = 400MB/s in 32bit mode or 200MB/s in 16 bit mode (cant remeber how the Z was wired),
dosent sound like much for displaying an image, but when we are talking about moives you have to factor in the write as well so 17MB/s becomes 37MB/s and with some moive formats you dont decode image 1 then 2 then 3 but 1 then 3 then 2 or some other wierd format (mpeg 4 with b frames bieng the worst) then you see that while the sustained read and wirte is the same, the peak burst speed is higher, basically you get stutering
then any type of buffering affects this and user spaace libries/programs might stage the data before copying it elswhere in memorey, so you see it adds up
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Still, as long as we could use the SRAM in QVGA mode it will be ideal for all the emulators, most of which don't need a higher res than 320x240.
And it'll be great for QVGA phones like then OpenEZX ones...
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Cool, sense this is in general discussion.....Can we use this kernel on sharp/cacko? OZ is nice but it doesn't have the software support. That's the only thing stopping me, not the kernel.
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perhaps, but it would be more work than anyone is willing to put into it
"software support" is a tricky thing and is the same exscuse microsoft uses. it all comes down to what you are running on your Z, i havent had a problem but then again my needs from the Z are very diffrent from most people on the board.
ethier way, i see the futre as video cards on chip and ddr ram, the pxa290 will have ddr support and most other pda chips i have seen follow this route as well, sram seems to be better used as cache as it increses the cost dramatically of the chip and it would be cheaper to just add ddr support and stick to the extra bandwidth of the ddr bus
couple this with the fact that there is no real improvment over going past 640x480 at 4" diagonal. perhaps to 800x600 but i suspect it will be more of a marketing move as higher res means more ram, cpu power and display power to drive the thing.
time will tell in the mean time they need to look at lowering the power requirements, i think it was stupid for intel to go to 1Ghz on thier PXA range with only a 20% increse in MIPS/calculation power. i guess it was to compete with MIPS but that is only an uneducated guess. i think for what they are aiming for (consumer device) intergrated graphics would have been a better option even if it does typecast thier part to PMP or PDA (for network routors your better off with an xscale chip which already has DDR support as well as QDR (quad data rate) and PCI/PCI-X/PCI-E)
sorry to jack the thread but is there anything eles anyone would like to know about the chip?
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Can we use this kernel on sharp/cacko? [div align=\"right\"][a href=\"index.php?act=findpost&pid=143400\"][{POST_SNAPBACK}][/a][/div]
No. SharpROMs does not support 2.6 kernels and will never do.