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

[Ajay kumar]

Hi Simon,

On Thu, Oct 3, 2013 at 7:51 PM, Simon Glass <sjg at chromium.org> wrote:

> 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
>
> You are right. I found it.
http://permalink.gmane.org/gmane.comp.video.dri.devel/78840
This patch would be resent in next series of iommu patches.
So, we would not need the u-boot patch anymore!

> >>
> >> Amicalement,
> >> --
> >> Albert.
> >> _______________________________________________
> >> U-Boot mailing list
> >> U-Boot at lists.denx.de
> >> http://lists.denx.de/mailman/listinfo/u-boot
> >
> >
>
Thanks and regards,
Ajay Kumar