Hi, >> > The of_configure_dma() function configures both the DMA masks and ops. >> > Moving DMA ops configuration to probe time would thus also delay >> > configuration of the DMA masks, which might not be safe. To avoid issues >> >> Do we know any example cases when it might be unsafe? I think we kind >> of rely on the fact that DMA mapping (and so DMA masks as well) is not >> used before probing the device anyway, because we let the IOMMU >> attachment happen at probe time, which essentially makes any earlier >> attempts to use DMA mapping on such device incorrect. > >I don't know of any such situation, but (if I remember correctly) when I >discussed the IOMMU rework with Arnd Bergman and Will Deacon there was a >concern that someone, somewhere was relying on the mask being set early. > >I personally would like to drop this patch, but it might be difficult to >ensure this wouldn't cause a regression. There should certainly be no DMA >mapping created before IOMMU attachment, but the DMA mask could possibly be >used somewhere else. > Infact i also wanted this to be dropped and to have masks also done along with ops, but thought of getting some feedback if its really needed before probe anywhere.
Regards, Sricharan _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
