[U-Boot] [PATCH 2/2] RFC: exynos: Disable the display controller when starting Linux

[Albert ARIBAUD <albert.u.boot@aribaud.net>]

Hi Ajay,

On Thu, 03 Oct 2013 14:34:20 +0530, Ajay Kumar
<ajaykumar.rs@samsung.com> wrote:

> If the exynos display controller is still active when Linux starts,
> then it will result in a kernel panic while FIMD sysmmu driver is
> getting probed.
> Calling exynos_fimd_lcd_disable() before jumping into kernel
> disables the display controller by switching off the windows,
> hence resolving the kernel panic which arises from sysmmu driver.
> 
> Create an Exynos specific definition for the weak function
> arch_cleanup_before_linux(), and then place the call to
> exynos_fimd_lcd_disable() inside the overrided definition of
> arch_cleanup_before_linux().
> 
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---

Why should the fix to this situation be making U-Boot disable the
display controller rather than making Linux able to cope with an
already active display controller?

Besides, fixing Linux would allow seamless booting displays, without an
ugly off-on glitch.

Amicalement,
-- 
Albert.