On Mon, May 18, 2009 at 3:11 PM, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > On Sat, May 16, 2009 at 01:05:50PM +0300, Felipe Contreras wrote: >> This allows devices to be registered only when they are used. The >> current dsp-bridge driver for example is not using iommu so registering >> the iommu iva2 device would conflict. By allowing remote registration >> the dsp-bridge can decide when the iommu iva2 device is registered. > > I don't think that this is a good idea - what happens if two people > call omap_iommu_add() for the same IOMMU device independently? Hmm, right, some extra checks would be needed to see if the device is already registered and then increase some refcount. That's more complicated that I was hoping for. > The real problem here seems to be the TI DSP bridge code, and if that's > the case why can't we just avoid registering IVA2 if the TI DSP bridge > code is enabled. That solves your stated problem without creating > additional management issues. The bridgedriver is expected to move and use iommu eventually, but not right now, so I guess the iva2 device should be registered only if MPU_BRIDGE_IOMMU is defined. But then what's the point of having the isp iommu device if the camera driver is disabled? Wouldn't that be wasting resources? Then if CAMERA is not defined the isp device should not be registered either. And finally if none of the two are enabled then you don't really iommu. By having omap_iommu_add all the dependencies would be handled automatically, right? 'modprobe bridgedriver' would load iommu. -- Felipe Contreras -- 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
