Re: [PATCH 1/1] ARM: dts: Make DP a consumer of DISP1 power domain on Exynos5420

From: Krzysztof Kozlowski
Date: Mon Apr 13 2015 - 06:59:19 EST

2015-04-13 5:30 GMT+09:00 Javier Martinez Canillas
> Commit ea08de16eb1b ("ARM: dts: Add DISP1 power domain for exynos5420")
> added a device node for the Exynos5420 DISP1 power domain but dit not
> make the DP controller a consumer of that power domain.
> This causes an "Unhandled fault: imprecise external abort" error if the
> exynos-dp driver tries to access the DP controller registers and the PD
> was turned off. This lead to a kernel panic and a complete system hang.
> Make the DP controller device node a consumer of the DISP1 power domain
> to ensure that the PD is turned on when the exynos-dp driver is probed.
> Fixes: ea08de16eb1b ("ARM: dts: Add DISP1 power domain for exynos5420")
> Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
> ---
> Hello,
> This latent bug was not exposed before since drivers for other devices
> marked as DISP1 power domain consumers were probed before exynos-dp so
> the PD was already on which made possible to access the DP registers.
> But "regulator: Defer lookup of supply to regulator_get" [0] that is in
> linux-next from a couple of days now, changed the order on which the
> drivers' probes succeed so the PD was disabled during exynos-dp probe.
> Exynos5420 machines with a display such as the Exynos5420 Peach Pit and
> Exynos5800 Peach Pi were failing to boot due this issue, i.e: [1].
> Olof,
> Could you please confirm $subject fixes the issue catched by your farm?
> Krzysztof,
> This patch conflicts with your Exynos5 phandle notation cleanup [2] but
> I preferred to send it on top of linux-next instead of making your series
> a dependency since it fixes a very important bug that had caused -next to
> be broken on these matchines for days now.

Sure, I don't mind. My patchset is just a cleanup so it can wait and
should not block important stuff.

Best regards,
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