Problems with u-boot/linux-fslc on mx6ul evk

Problems with u-boot/linux-fslc on mx6ul evk

[Eric Nelson]

Hi all,

I'm not sure if this is a kernel issue (likely) or a
U-Boot issue, so I've cross-posted this to both the
U-Boot mailing list and here:
	http://lists.denx.de/pipermail/u-boot/2016-August/thread.html#265029

I just ran into a problem with bus frequency switching
on the EVK and there appears to be a U-Boot component.

Using the 4.1.15 kernel from git.freescale.com (commit a4d2a08)
and the latest U-Boot from Stefano's imx tree (commit a3e5519)
causes the EVK to hang during a bus frequency switch to LOW_POWER
mode.

The last gasp is this:
	Bus freq set to 24000000 start...

This is easy to reproduce by downing both ethernet interfaces
and blanking the display.

	ifconfig eth0 down
	ifconfig eth1 down
	echo 1 > /sys/class/graphics/fb0/blank


And the code block in question is here:
	http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/arch/arm/mach-imx/busfreq_ddr3.c?h=imx_4.1.15_1.0.0_ga#n386

When using the binary U-Boot 2015.07 from the EVK package (commit
d7d7c43 from git.freescale.com), the kernel gets through the
frequency switch and produces this message.

	Bus freq set to 24000000 done!

I first saw this problem with u-boot-fslc branch v2016.07
and linux-fslc (4.1.29 and 4.1.30).

Has anybody else experienced this?

Please advise,


Eric

Re: Problems with u-boot/linux-fslc on mx6ul evk

[Fabio Estevam]

Hi Eric,

On Sun, Aug 28, 2016 at 6:08 PM, Eric Nelson <eric@nelint.com> wrote:
> Hi all,
>
> I'm not sure if this is a kernel issue (likely) or a
> U-Boot issue, so I've cross-posted this to both the
> U-Boot mailing list and here:
>         http://lists.denx.de/pipermail/u-boot/2016-August/thread.html#265029
>
> I just ran into a problem with bus frequency switching
> on the EVK and there appears to be a U-Boot component.
>
> Using the 4.1.15 kernel from git.freescale.com (commit a4d2a08)
> and the latest U-Boot from Stefano's imx tree (commit a3e5519)
> causes the EVK to hang during a bus frequency switch to LOW_POWER
> mode.
>
> The last gasp is this:
>         Bus freq set to 24000000 start...
>
> This is easy to reproduce by downing both ethernet interfaces
> and blanking the display.
>
>         ifconfig eth0 down
>         ifconfig eth1 down
>         echo 1 > /sys/class/graphics/fb0/blank
>
>
> And the code block in question is here:
>         http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/arch/arm/mach-imx/busfreq_ddr3.c?h=imx_4.1.15_1.0.0_ga#n386
>
> When using the binary U-Boot 2015.07 from the EVK package (commit
> d7d7c43 from git.freescale.com), the kernel gets through the
> frequency switch and produces this message.
>
>         Bus freq set to 24000000 done!
>
> I first saw this problem with u-boot-fslc branch v2016.07
> and linux-fslc (4.1.29 and 4.1.30).
>
> Has anybody else experienced this?
>
> Please advise,

Thanks for reporting. I have just sent a fix for this to the U-Boot list.