On Tue, Jun 11, 2019 at 12:00 AM Keith Busch <keith.busch@xxxxxxxxx> wrote: > > On Mon, Jun 10, 2019 at 1:45 AM Daniel Drake <drake@xxxxxxxxxxxx> wrote: > > + /* We don't support sharing MSI interrupts between these devices */ > > + nrdev->bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI; > > And this is a problem, isn't it? Since we don't have an option to open > the MSI implementation in RAID mode your experience will be much > better to disable this mode when using Linux as per the current > recommendation rather than limping along with legacy IRQ. What's the specific problem that you see here? Is it that the interrupt delivery mechanism is legacy wire instead of MSI, or is the problem that the interrupt is shared over the whole set of storage devices? I installed Windows 10 on this product in RAID mode and it is using the legacy interrupt too. Also, on Linux, MSI interrupts have already been disabled on the AHCI part of such setups for a good while now: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f723fa4e69920f6a5dd5fa0d10ce90e2f14d189c The earlier patches from Dan Williams also had the design of sharing the legacy interrupt: https://marc.info/?l=linux-ide&m=147709610621480&w=2 I think some kind of MSI support may be possible, perhaps something similar to what is done by drivers/pci/controller/vmd.c, but it needs a bit more thought, and I was hoping that we could get the base device support in place before investigating MSI as a separate step. However, if the concern you are raising is regarding the sharing of interrupts, I think that cannot change because the NVMe devices PCI config space is totally inaccessible when in this mode. That means there is no way we can configure a per-device MSI message, so the interrupt will continue to be shared regardless of delivery mechanism. Thanks, Daniel
