Re: [RESEND PATCH] ARM: EXYNOS: Fix failed second suspend on Exynos4
From: Krzysztof Kozlowski
Date: Mon Feb 23 2015 - 12:12:45 EST
2015-02-23 17:25 GMT+01:00 Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>:
> On Wednesday, February 18, 2015 11:45:25 AM Krzysztof Kozlowski wrote:
>> On Exynos4412 boards (Trats2, Odroid U3) after enabling L2 cache in
>> 56b60b8bce4a ("ARM: 8265/1: dts: exynos4: Add nodes for L2 cache
>> controller") the second suspend to RAM failed. First suspend worked fine
>> but the next one hang just after powering down of secondary CPUs (system
>> consumed energy as it would be running but was not responsive).
>> The issue was caused by enabling delayed reset assertion for CPU0 just
>> after issuing power down of cores. This was introduced for Exynos4 in
>> 13cfa6c4f7fa ("ARM: EXYNOS: Fix CPU idle clock down after CPU off").
>> The whole behavior is not well documented but after checking with vendor
>> code this should be done like this (on Exynos4):
>> 1. Enable delayed reset assertion when system is running (for all CPUs).
>> 2. Disable delayed reset assertion before suspending the system.
>> This can be done after powering off secondary CPUs.
>> 3. Re-enable the delayed reset assertion when system is resumed.
>> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
>> Fixes: 13cfa6c4f7fa ("ARM: EXYNOS: Fix CPU idle clock down after CPU off")
>> Cc: <stable@xxxxxxxxxxxxxxx>
> It turned out that this patch is also needed to fix cpuidle AFTR mode
> hang on Trats2.
> Tested-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Thanks for testing.
Could you pick it up for this RC cycle? This patch fixes fatal suspend
and cpuidle failures on Exynos4 based boards on current mainline.
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