[U-Boot] [RFC]: always relocate u-boot before the framebuffer

Jeroen Hofstee jeroen at myspectrum.nl
Thu Jan 3 19:10:42 CET 2013


Hi,

On 01/03/2013 11:41 AM, Wolfgang Denk wrote:
> In message <50E55D24.8000809 at myspectrum.nl> you wrote:
>> As Wolfgang suggested, maybe I shouldn't point at U-boot but blame
>> linux and get rid of the 2MB alignment. I haven't checked yet, but I
>> don't see why that should not work. So this is resolved for my
>> case (thanks for the suggestion) for now until I meet
>>
>> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg80440.html
> Hm...
>
> In any case the code should behave the same in U-Boot and Linux.  If
> we can lift this restriction in Linux, then OK.  If not, then the FB
> allocation in U-Boot (by lcd_setmem()) should result in the same size
> as allocated by Linux.  After all, the allocated size should be a
> "resasonable" one ;-)

For completeness, removing size = ALIGN(size, SZ_2M); from vram.c
in the linux dss driver and passing the correct vram= works fine.
The frame buffer is then at the same physical address and I regain
15MB of memory. So solved as far as I am concerned till proven that
it really hurts performance.

Motivation for the 2mb alignment is at:
http://lists.infradead.org/pipermail/linux-arm-kernel/2010-December/035013.html

Regards,
Jeroen


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