Hi Eric, On 26/07/2013 16:04, Eric Nelson wrote:
> > The real question we have regarding DT is the timing. We're shipping > DT files on secondary storage (SATA/SD card), and want/need something > local (i.e. env in SPI-NOR) to present a U/I if either no storage > available or if something goes wrong. ok, understood. > > A secondary need/desire is to have something simple for configuring > a new display. The process of tuning some of the parameters (esp > margins) can sometimes be iterative because the data sheets aren't > always clear and clock options are often imprecise. Since this > iteration and configuration is often done by EEs in a lab who > don't have an easy way to recompile a DTS, our inclination is > to do something locally. ok, I understand the point. Maybe it should be even more simple for the EEs if the would be such kind of special u-boot commands, able to set the timing and reload the framebuffer. Can be a solution using the u-boot's fdt library enough ? With "fdt get" and "fdt set" it is possible to read and modify a DT in memory, and then the modified DT can be stored back - avoiding to compile directly the DTS. > > Is Tegra somehow using DT to configure U-Boot display? > I'm not finding the code. ./board/compal/dts/tegra20-paz00.dts seems doing that, but I have no experience with it ;( My thoughts are more related by comparing what the kernel does and how the timing is configured. There are several examples (I am seeing the imx23-dts, but it is not the only one) where the complete timing for a panel is done inside the DT. As you have already checked, using a U-Boot variable has some limitations, because it does not contain all parameters that are needed. And I think it could be quite difficult to get it general for all SOCs because some SOCs need some specialties (VRAM for OMAP could be an example). > No matter how we end up doing this, passing U-Boot's display > setup to the kernel via DT is the **right thing**, so that > there aren't two bits to maintain. Yes, I think we do not need to discuss how to pass to the kernel - but I am checking if it is a suitable way to configure the u-boot display,too. Anyway, I agree that using a U-Boot variable is much more simple to implement.. Best regards, Stefano -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
