Messages in this thread | | | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: [RESEND PATCH] ARM: EXYNOS: Fix failed second suspend on Exynos4 | Date | Mon, 23 Feb 2015 17:25:48 +0100 |
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Hi,
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@samsung.com> > Fixes: 13cfa6c4f7fa ("ARM: EXYNOS: Fix CPU idle clock down after CPU off") > Cc: <stable@vger.kernel.org>
It turned out that this patch is also needed to fix cpuidle AFTR mode hang on Trats2.
Tested-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics
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