Hi Robin, On Mon, Jan 23, 2017 at 9:34 PM, Robin Murphy <robin.murphy@xxxxxxx> wrote: > Hi Magnus, > > On 23/01/17 12:12, Magnus Damm wrote: >> From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx> >> >> Consider failure of iommu_get_domain_for_dev() as non-critical and >> get rid of the warning printout. This allows IOMMU properties to be >> included in the DTB even though the kernel is configured with >> CONFIG_IOMMU_API=n or in case a particular IOMMU driver refuses to >> enable IOMMU support for a certain slave device and returns error >> from the ->add_device() callback. >> >> This is only a cosmetic change that removes console warning printouts. > > The warning is there for a reason - at this point, we *expected* the > device to be using an IOMMU for DMA, so a failure is significant. Rather > than masking genuine failures in other cases because your case > deliberately breaks that expectation, simply change the expectation - > i.e. rather than letting of_xlate() succeed then failing add_device() > later, reject the of_xlate() call up-front such that the DMA layer never > gets told about the IOMMU in the first place. Thanks for pointing me in the right direction! I will try to handle this in xlate() instead. Cheers, / magnus
