On 09/21/2012 10:22 AM, Anatolij Gustschin wrote:
Hi Eric,
On Fri, 21 Sep 2012 09:38:23 -0700
Eric Nelson<eric.nel...@boundarydevices.com> 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.
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