On Fri 2018-03-09 16:13:36, Suman Anna wrote: > On 03/09/2018 06:08 AM, Robin Murphy wrote: > > On 08/03/18 18:50, Pavel Machek wrote: > >> Hi! > >> > >>>> * Pavel Machek <pavel@xxxxxx> [180308 14:31]: > >>>>> Hi! > >>>>> > >>>>> I'm getting this warning... Has anyone seen/debugged that before? > >>>>> Unfortunately the backtrace does not seem to be too useful :-(. > >>>> > >>>> Adding Suman to Cc, as it points to arm_iommu_release_mapping(). > >>> > >>> Hmm, we need to find out if the failure paths in isp_probe() are > >>> mismatched, or if this is coming from some mismatch between the OMAP > >>> IOMMU driver and the DMA plumbing. AFAIK, the cleanup paths in this > >> > >> Well, camera only started to work on N900 pretty recently. Let me add > >> some debug printks... > >> > >> Camera does not work in 4.16.0-rc4-next-20180308-dirty. > >> > >> I see this. It looks like problem in isp error paths, indeed: > > > > Well, there certainly seems to be an obvious bug wherein > > isp_detach_iommu() just releases the mapping directly without calling > > arm_iommu_detach_device() to balance the equivalent attach. That can't > > be helping. > > Indeed, I have been able to reproduce the same warning using a > standalone test module, and the missing arm_iommu_detach_device() is > causing the warning after probe (during failure path) or during > remove. Ok do you have an idea how to fix the isp error paths? Untested patch would be fine... But it seems that you know what needs to be fixed and I don't. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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