Unable to boot mainline on snow chromebook since 3.15

[dianders@chromium.org (Doug Anderson)]

Will,

On Wed, Sep 10, 2014 at 4:17 AM, Will Deacon <will.deacon@arm.com> wrote:
> On Mon, Sep 08, 2014 at 03:05:40PM +0100, Javier Martinez Canillas wrote:
>> Hello Will,
>
> Hi Javier,
>
>> Since many folks don't agree that hacking different subsystems is the way
>> forward I'll hold the patches and don't post them. The sunxi thread [0]
>> already shows how different people have strong opposite positions on the
>> correct approach to handle this.
>>
>> For now you can just disable the tps65090 PMIC support by not enabling the
>> CONFIG_REGULATOR_TPS65090 kconfig symbol on your kernel config. That will give
>> you exactly the same behavior that before tps65090 support was added to the
>> Snow DT on commit b16be76 ("ARM: dts: add tps65090 power regulator for
>> exynos5250-snow") which AFAIU was good enough for your workflow.
>
> Disabling the regulator support gives me my framebuffer back, thanks.

Yay!  Is this good enough to tide you over until DRM support lands?


> I
> then get stuck mounting my root filesystem over sd card because it's
> reported as read-only. The following hack solved the issue, but I'm not
> exactly sure where this regression has come from (whether this is a board
> quirk or pinctrl is really misconfigured).

This is a regression that was introduced by:

9795a84 mmc: dw_mmc: remove dw_mci_of_cd_gpio/wp_gpio()

In "exynos5250-cros-common.dtsi" you can see that the "wp-gpios =
<&gpc2 1 0>;" is still listed under the slot node.  Nobody is looking
there anymore.

This is fixed in linux-next by:

aaa25a5 ARM: dts: unuse the slot-node and deprecate the
supports-highspeed for dw-mmc in exynos


I'll let Kukjin decide what he wants to do about the regression in
v3.17 (how to deal with conflicts, backporting, etc).


-Doug