From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Nelson Date: Fri, 21 Sep 2012 10:44:21 -0700 Subject: [U-Boot] Disabling video in bootm (cleanup_before_linux) In-Reply-To: <20120921192204.3b48d3f3@wker> References: <505C97FF.7000709@boundarydevices.com> <20120921192204.3b48d3f3@wker> Message-ID: <505CA775.5080308@boundarydevices.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 09/21/2012 10:22 AM, Anatolij Gustschin wrote: > Hi Eric, > > On Fri, 21 Sep 2012 09:38:23 -0700 > Eric Nelson wrote: > >> Hi all, >> >> While looking into some trouble booting the latest Linux kernel patches >> for i.MX6 display support, I found that the kernel driver was thrown off by >> the interrupt status bits in the i.MX6 IPU. >> >> Until and unless we have the ability to hand off a 'live' display, it seems >> that we should disable the video driver as a part of the 'bootm' process. >> >> At the very least, doing this will avoid the possibility of trash on the >> display during the transition. >> >> I've been looking, and I don't see a place to tap into this process. >> It seems that having a shutdown routine for the display drivers >> (cfb_console?) is the way to go. > > cfb_console driver is a renderer of the characters and bitmaps > to the framebuffer memory and is not a good place for a shutdown > routine, I think. But we can add a shutdown function to the IPU > driver drivers/video/mxc_ipuv3_fb.c and call it before booting. > bootm code in common/cmd_bootm.c has a weak arch_preboot_os() > function that can be overridden by platform specific preboot > routine. We could define a preboot function in > > arch/arm/cpu/armv7/mx6/soc.c > or in > arch/arm/cpu/armv7/imx-common/cpu.c > > and call IPU shutdown routine in it. > Thanks Anatolij. This is just what we need. I'll send a patch shortly.