On Tue, Apr 09, 2019 at 08:53:03PM +0800, Zhen Lei wrote: > +static int __init iommu_dma_mode_setup(char *str) > +{ > + if (!str) > + goto fail; > + > + if (!strncmp(str, "passthrough", 11)) > + iommu_default_dma_mode = IOMMU_DMA_MODE_PASSTHROUGH; > + else if (!strncmp(str, "lazy", 4)) > + iommu_default_dma_mode = IOMMU_DMA_MODE_LAZY; > + else if (!strncmp(str, "strict", 6)) > + iommu_default_dma_mode = IOMMU_DMA_MODE_STRICT; > + else > + goto fail; > + > + pr_info("Force dma mode to be %d\n", iommu_default_dma_mode); Printing a number is not very desriptive or helpful to the user. Please print the name of the mode instead. Regards, Joerg