Hi, We're working with a number of platforms based on Intel Apollo Lake and there are some clues suggesting that the IR-PCI-MSI irqchip functionality would be able to get us out of a tricky situation described at:
ath9k hardware corrupts MSI Message Data, raises wrong interrupt http://marc.info/?l=linux-pci&m=150238260726797&w=2 However the affected platforms do not have a DMAR table present. And I read in the IntelĀ® Virtualization Technology for Directed I/O spec: "The system BIOS is responsible for detecting the remapping hardware functions in the platform and for locating the memory-mapped remapping hardware registers in the host system address space. The BIOS reports the remapping hardware units in a platform to system software through the DMA Remapping Reporting (DMAR) ACPI table". Unfortunately since the BIOS authors have not done what the spec asked, this nice hardware functionality is completely unavailable :( For now we will have to find an alternative approach to solve the problem (BIOS can't be changed), but I am curious if there are plans to have Linux automatically probe the IOMMU through some other means, given that BIOS authors are apparently not providing the DMAR table in many cases. Thanks Daniel _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu