Messages in this thread | | | Date | Thu, 12 Oct 2023 20:57:40 +0800 | Subject | Re: [PATCH v5 2/7] iommu: Decouple iommu_present() from bus ops | From | Baolu Lu <> |
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On 2023/10/12 20:37, Jason Gunthorpe wrote: > On Thu, Oct 12, 2023 at 12:40:01PM +0100, Robin Murphy wrote: >> On 2023-10-12 07:05, Baolu Lu wrote: >>> On 10/12/23 2:14 AM, Robin Murphy wrote: >>>> Much as I'd like to remove iommu_present(), the final remaining users >>>> are proving stubbornly difficult to clean up, so kick that can down the >>>> road and just rework it to preserve the current behaviour without >>>> depending on bus ops. Since commit 57365a04c921 ("iommu: Move bus setup >>> >>> The iommu_present() is only used in below two drivers. >>> >>> $ git grep iommu_present >>> drivers/gpu/drm/mediatek/mtk_drm_drv.c: if >>> (!iommu_present(&platform_bus_type)) >>> drivers/gpu/drm/tegra/drm.c: if (host1x_drm_wants_iommu(dev) && >>> iommu_present(&platform_bus_type)) { >>> >>> Both are platform drivers and have the device pointer passed in. Just >>> out of curiosity, why not replacing them with device_iommu_mapped() >>> instead? Sorry if I overlooked previous discussion. >> >> Yes, we've already gone round in circles on this several times, that's why >> it's explicitly called out as "stubbornly difficult" in the commit message. >> The Mediatek one is entirely redundant, but it seems I have yet to figure >> out the right CC list to get anyone to care about that patch[1].
I see now. Thanks for the explanation.
> > Please just have Joerg take such a trivial patch, there is no reason > we need to torture outselves because DRM side is not behaving well. :(
I was not object to the patch. Just want to make sure that I understand the reason why device_iommu_mapped() can't be used in those two drivers.
It's fine to me. I will add my r-b.
Best regards, baolu
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