On Wednesday 30 March 2011 15:50:37 Sakari Ailus wrote: > Laurent Pinchart wrote: > > Hi Sakari, > > Hi Laurent, > > > On Wednesday 30 March 2011 10:16:56 Sakari Ailus wrote: > >> Laurent Pinchart wrote: > >>> On Friday 25 March 2011 20:37:55 Ramirez Luna, Omar wrote: > >>>> On Fri, Mar 25, 2011 at 10:13 AM, Sakari Ailus wrote: > >>>>> Hi, > >>>>> > >>>>> This patchset is aimed to fix a problem in arch_iommu implementation > >>>>> references. When an actual arch_iommu implementation is not loaded > >>>>> while iommu_get() is being called results to a kernel oops, as well > >>>>> as removing an arch_iommu implementation which is in use. > >>>> > >>>> How about fixing the dependency instead? Right now iommu2 depends on > >>>> iommu because of the calls to > >>>> install_iommu_arch/uninstall_iommu_arch... we should change that > >>>> dependency to iommu depend on iommu2. Something like iommu (plat) > >>>> querying iommu2 (mach) for devices to install. > >>> > >>> The reason why iommu depends on iommu2 and not the other way around is > >>> because several mach-specific iommu implementations should be able to > >>> coexist in the same kernel. The right one should be loaded at runtime. > >>> > >>> I think that Sakari's patches correcty fix the problems he noticed. > >>> However, they won't fix one basic issue, which is that the iommu2 > >>> module won't be automatically pulled in when the omap3isp module is > >>> loaded. The omap3isp driver will then fail to probe the device. That's > >>> better than crashing though. > >> > >> One option would be to specify the name of the module in the platform > >> data and request_module() that in omap_iommu_probe(). This would solve > >> the issue, not sure how pretty is this though. > > > > Do we need that ? My understanding is that a machine will need a single > > mach- specific iommu implementation only. Drivers shouldn't need to care > > about that. > > Well, no more than that there would have to be a driver for the IOMMU > for that very hardware. > > > The iommu implementation should be automatically selected based on the > > machine time. > > Machine type? > > I agree, but where is the selection made? The selection can be made by board code, or by the iommu implementations themselves if they're compiled in. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
