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From: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
To: Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>
Cc: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH 2/2] iommu/rockchip: Move irq request past pm_runtime_enable
Date: Tue, 07 Aug 2018 13:45:26 +0200	[thread overview]
Message-ID: <2114757.JfhfUCyzvi@phil> (raw)
In-Reply-To: <20180807085406.3863-3-marc.zyngier-5wv7dgnIgG8@public.gmane.org>

Am Dienstag, 7. August 2018, 10:54:06 CEST schrieb Marc Zyngier:
> Enabling the interrupt early, before power has been applied to the
> device, can result in an interrupt being delivered too early if:
> 
> - the IOMMU shares an interrupt with a VOP
> - the VOP has a pending interrupt (after a kexec, for example)
> 
> In these conditions, we end-up taking the interrupt without
> the IOMMU being ready to handle the interrupt (not powered on).
> 
> Moving the interrupt request past the pm_runtime_enable() call
> makes sure we can at least access the IOMMU registers. Note that
> this is only a partial fix, and that the VOP interrupt will still
> be screaming until the VOP driver kicks in, which advocates for
> a more synchronized interrupt enabling/disabling approach.
> 
> Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support")
> Signed-off-by: Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>

Reviewed-by: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>

      parent reply	other threads:[~2018-08-07 11:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-07  8:54 [PATCH 0/2] iommu/rockchip: Runtime PM fixes Marc Zyngier
2018-08-07  8:54 ` [PATCH 1/2] iommu/rockchip: Handle errors returned from PM framework Marc Zyngier
     [not found]   ` <20180807085406.3863-2-marc.zyngier-5wv7dgnIgG8@public.gmane.org>
2018-08-07 12:09     ` Heiko Stuebner
2018-08-07 12:31       ` Marc Zyngier
     [not found]         ` <94b6aab1-e8d3-6929-a2e6-2f06c564bc70-5wv7dgnIgG8@public.gmane.org>
2018-08-07 13:15           ` Heiko Stuebner
2018-08-07 14:25             ` Marc Zyngier
     [not found]               ` <5aa8d184-0c58-3471-a661-8a66a93271c7-5wv7dgnIgG8@public.gmane.org>
2018-08-08  6:30                 ` Heiko Stuebner
2018-08-08  6:33     ` Heiko Stuebner
2018-08-07  8:54 ` [PATCH 2/2] iommu/rockchip: Move irq request past pm_runtime_enable Marc Zyngier
     [not found]   ` <20180807085406.3863-3-marc.zyngier-5wv7dgnIgG8@public.gmane.org>
2018-08-07 11:45     ` Heiko Stuebner [this message]

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