Vaibhav, Thanks for your help on this. I was unaware that the Kernel changed the pin-mux after U-boot did the initial setup. Applying this fix to the linux kernel fixed the problem. Much appreciated, Neil Johnson On Mon, May 7, 2012 at 11:21 PM, Hiremath, Vaibhav <hvaibhav@xxxxxx> wrote: > > On Tue, May 08, 2012 at 04:41:35, Neil Johnson wrote: > > Linux OMAP list: > > > > We are proving out the DVI output on a DM3730 board that we've > > designed, and we're seeing something strange: Our output to the video > > window is always red. We see the penguin show up in the corner, and > > text/graphics show up, but the red channel is always on for all pixels > > on the screen. > > > > Studying our schematic and comparing with the Beagleboard-xm > > schematic, it appears that we're hooking everything up the same way, > > with just some subtle differences: > > > > We desire to output 1280x720 resolution (720p), and that means we need > > to use the alternate configuration for the DSS output pins, as > > mentioned in the DM3730 TRM: > > > > On Page 1564, it states: > > > > The DISPC_DATA_LCD[5:0] data multiplexed with the DSI signals on > > dss_data[5:0] pads is limited to up to 60 MHz pixel clock frequency. > > If the parallel 18/24-bit interface in bypass mode with a pixel clock > > above 60 MHz is required, the DISPC_DATA_LCD[5:0] multiplexed on > > dss_data[23:18] pads, and DISPC_DATA_LCD[23:18] multiplexed on > > sys_boot pads must be used. > > > > So, we've mapped DISPC_DATA_LCD[5:0] to dss_data[23:18] pads and > > routed DISPC_DATA_LCD[23:18] to be multiplexed with the sys_boot pads. > > > > Our sys_boot pads are all pulled up to 1.8 V through 4.7 K-ohm > > resistors. I'm suspicious that this is causing the red lines to be > > pulled high, generating red pixels all the time. Am I off-base here? > > Is there something I'm missing, like the U-boot mux configuration or > > something? What can I check from a software level to verify that all > > is correct? According to the Beagle-board-xm manual, the board > > auto-detects which way things are hooked up, but maybe I haven't > > grabbed that code from the beagleboard board file? Thanks, > > > > > Make sure that you have configured the pin mux settings accordingly, > We have similar interface done on OMAP3EVM, so you can refer to the > Omap3evm code, > > http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap.git;a=blob;f=arch/arm/mach-omap2/board-omap3evm.c;h=fd1b481c762c97576f1c9cb5503e9bd470a4a528;hb=5e136da4f5d9aa5388097afad1f6a0e6fd8572c6#l556 > > Thanks, > Vaibhav -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
