On Fri, Jul 04, 2014 at 02:47:10PM +0100, Thierry Reding wrote: > On Fri, Jul 04, 2014 at 01:05:30PM +0200, Joerg Roedel wrote: > > On Thu, Jun 26, 2014 at 10:49:41PM +0200, Thierry Reding wrote: > > > Add an IOMMU device registry for drivers to register with and implement > > > a method for users of the IOMMU API to attach to an IOMMU device. This > > > allows to support deferred probing and gives the IOMMU API a convenient > > > hook to perform early initialization of a device if necessary. > > > > Can you elaborate on why exactly you need this? The IOMMU-API is > > designed to hide any details from the user about the available IOMMUs in > > the system and which IOMMU handles which device. This looks like it is > > going in a completly different direction from that. > > I need this primarily to properly serialize device probing order. > Without it the IOMMU may be probed later than its clients, in which case > the client drivers will assume that there is no IOMMU (iommu_present() > for the parent bus fails). I can also vouch for needing *a* solution to this problem. The ARM SMMU (and I think others) rely on initcall ordering rather than the driver probing model to ensure the IOMMU is probed before any of its masters. Will -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
