On Fri, Feb 16, 2024 at 10:24:06PM +0530, Manivannan Sadhasivam wrote: > On Wed, Feb 14, 2024 at 02:38:57PM +0100, Krzysztof Kozlowski wrote: > > On 14/02/2024 13:54, Johan Hovold wrote: > > > On Wed, Feb 14, 2024 at 01:01:20PM +0100, Krzysztof Kozlowski wrote: > > >> On 12/02/2024 17:50, Johan Hovold wrote: > > >>> Whether the 'msi-map-mask' property is needed or not depends on how the > > >>> MSI interrupts are mapped and it should therefore not be described as > > >>> required. > > >> > > >> I could imagine that on all devices the interrupts are mapped in a way > > >> you need to provide msi-map-mask. IOW, can there be a Qualcomm platform > > >> without msi-map-mask? > > > > > > I don't have access to the documentation so I'll leave that for you guys > > > to determine. I do note that the downstream DT does not use it and that > > > we have a new devicetree in linux-next which also does not have it: > > > > > > https://lore.kernel.org/r/20240125-topic-sm8650-upstream-pcie-its-v1-1-cb506deeb43e@xxxxxxxxxx > > > > > > But at least the latter looks like an omission that should be fixed. > > > > Hm, either that or the mask for sm8450 was not needed as well. Anyway, > > thanks for explanation, appreciated! > > msi-map-mask is definitely needed as it would allow all the devices under the > same bus to reuse the MSI identifier. Currently, excluding this property will > not cause any issue since there is a single device under each bus. But we cannot > assume that is going to be the case on all boards. Are you saying that there is never a use case for an identity mapping? Just on Qualcomm hardware or in general? It looks like we have a fairly large number of mainline devicetrees that do use an identity mapping here (i.e. do not specify 'msi-map-mask') and the binding document also has an explicit example of this. Documentation/devicetree/bindings/pci/pci-msi.txt > I will submit a patch to fix SM8650. Johan
