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

[Simon Glass]

Hi,

On Thu, Oct 3, 2013 at 3:24 AM, Ajay kumar <ajaynumb at gmail.com> wrote:
> +Simon Glass
>
>
> On Thu, Oct 3, 2013 at 2:25 PM, Albert ARIBAUD <albert.u.boot at aribaud.net>
> wrote:
>>
>> Hi Ajay,
>>
>> On Thu, 03 Oct 2013 14:34:20 +0530, Ajay Kumar
>> <ajaykumar.rs at 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 at samsung.com>
>> > Signed-off-by: Simon Glass <sjg at 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.

Yes, I believe this bug was fixed in Linux - Ajay do you know? Perhaps
the fix has not been upstreamed yet?

Regards,
Simon

>>
>> Amicalement,
>> --
>> Albert.
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>
>