Re: [PATCH 0/8] iommu: Make core iommu-groups code more generic

From: Joerg Roedel
Date: Thu Nov 19 2015 - 08:41:20 EST

Hi Yong Wu,

On Thu, Nov 19, 2015 at 04:13:21PM +0800, Yong Wu wrote:
> (151119_13:39:37.472)WARNING:
> at /proj/mtk40525/upstreamdev/v4.4/kernel/mediatek/drivers/iommu/iommu.c:1154
> (151119_13:39:37.472)Modules linked in:
> (151119_13:39:37.472)CPU: 1 PID: 731 Comm: sh Not tainted 4.4.0-rc1+
> #37
> (151119_13:39:37.472)Hardware name: MediaTek MT8173 evaluation board
> (DT)
> (151119_13:39:37.472)task: ffffffc076bb4d00 ti: ffffffc076bdc000
> task.ti: ffffffc076bdc000
> (151119_13:39:37.472)PC is at iommu_detach_device+0x5c/0xb0
> (151119_13:39:37.472)LR is at iommu_detach_device+0x30/0xb0
> xxx

This warning triggers when you use iommu_detach_device() with a device
that is in a group with other devices. For those devices you must
attach/detach the whole group of devices.

For that you have to use iommu_detach_group() and iommu_attach_group().


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