[U-Boot] [PATCH v2] arm: am33xx: Initialize EMIF REG_PR_OLD_COUNT for BBB and am335x-evm

Tom Rini trini at konsulko.com
Thu Dec 8 15:30:18 CET 2016


On Thu, Dec 08, 2016 at 12:19:01PM +0200, Jyri Sarha wrote:

> Initialize EMIF OCP_CONFIG registers REG_COS_COUNT_1, REG_COS_COUNT_2,
> and REG_PR_OLD_COUNT field for Beaglebone-Black and am335x-evm. With
> the default values LCDC suffers from DMA FIFO underflows and frame
> synchronization lost errors. The initialization values are the highest
> that work flawlessly when heavy memory load is generated by CPU. 32bpp
> colors were used in the test. On BBB the video mode used 110MHz pixel
> clock. The mode supported by the panel of am335x-evm uses 30MHz pixel
> clock.
> 
> Signed-off-by: Jyri Sarha <jsarha at ti.com>

Reviewed-by: Tom Rini <trini at konsulko.com>

But, does TI have a whitepaper or tech pub or anything that describes
how one would calculate that value on a custom design?  Tweaking that
for optimal usage is something I know happens in some cases and could be
used in a lot more.  If there's a doc that explains how to figure it
out, it would be good to link to it in the comments in the patch as
well.  Since I don't know that such a thing does exist I'll reviewed-by
it now tho.  Thanks!

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20161208/6168bf2b/attachment.sig>


More information about the U-Boot mailing list