From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Cc: linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Bartlomiej Zolnierkiewicz
<b.zolnierkie-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Subject: Re: [PATCH 1/2] iommu: call detach also for default_domain before attaching to new one
Date: Wed, 17 Feb 2016 12:14:50 +0100 [thread overview]
Message-ID: <20160217111450.GA18805@8bytes.org> (raw)
In-Reply-To: <56C422AE.9000108-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
On Wed, Feb 17, 2016 at 08:35:10AM +0100, Marek Szyprowski wrote:
> Huh, I wasn't aware of this change in the iommu drivers api. For some
> drivers attach/detach callbacks does something more than just programming
> page table base register, like for example in case of exynos iommu it is
> enabling runtime power management and clocks. The code is really
> much simpler
> if those calls are balanced, but if the goal is to allow multiple
> unballanced
> attach calls, I will try to fix this in our driver.
>
> Maybe it should be documented somewhere, that attach calls can be
> unbalanced?
Well, when your driver uses default-domains, the detach_dev call-back is
not used anymore. The attach_dev call-back is supposed to just overwrite
any existing binding that may exist for the device. So the calls are not
unbalanced, the detach_dev calls just don't happen anymore.
Joerg
next prev parent reply other threads:[~2016-02-17 11:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-16 14:40 [PATCH 0/2] iommu: fix handling of attach/detach for default domains Marek Szyprowski
[not found] ` <1455633632-16873-1-git-send-email-m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2016-02-16 14:40 ` [PATCH 1/2] iommu: call detach also for default_domain before attaching to new one Marek Szyprowski
[not found] ` <1455633632-16873-2-git-send-email-m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2016-02-16 15:59 ` Joerg Roedel
[not found] ` <20160216155922.GV18805-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2016-02-17 7:35 ` Marek Szyprowski
[not found] ` <56C422AE.9000108-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2016-02-17 11:14 ` Joerg Roedel [this message]
[not found] ` <20160217111450.GA18805-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2016-02-17 14:42 ` Marek Szyprowski
[not found] ` <56C486EE.5020504-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2016-02-25 14:01 ` Joerg Roedel
2016-02-16 14:40 ` [PATCH 2/2] iommu: fix default domain handling in __iommu_detach_group() Marek Szyprowski
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