From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Thu, 8 Dec 2016 09:30:18 -0500 Subject: [U-Boot] [PATCH v2] arm: am33xx: Initialize EMIF REG_PR_OLD_COUNT for BBB and am335x-evm In-Reply-To: <1481192341-3729-1-git-send-email-jsarha@ti.com> References: <1481192341-3729-1-git-send-email-jsarha@ti.com> Message-ID: <20161208143018.GS4248@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 Reviewed-by: Tom Rini 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: