On Mon, Aug 28, 2017 at 7:23 AM, Lucas Stach <l.stach@xxxxxxxxxxxxxx> wrote: > Hi all, > > this small series tries to fix/workaround a serious design flaw of the DWC PCIe > host controller: it is unable to work with both legacy and MSI IRQs enabled at > the same time. As soon as the first MSI is enabled in the DWC MSI controller, > the host stops forwarding legacy IRQs. > > If the MSI controller is present, MSIs will be used for the PCIe port services > IRQs, leaving endpoint devices which don't support MSIs unable to raise IRQs. > It is only safe to enable the MSI controller if it is validated that all PCIe > devices and drivers in the system support working MSIs. As most devices > support falling back to using legacy PCIe IRQs if MSI support is missing it is > much safer to disable the MSI by default and only enable it on validated > systems. > > Feedback welcome. > > Regards, > Lucas > > Lucas Stach (3): > PCI: designware: only register MSI controller when MSI irq line is > valid > PCI: imx6: allow MSI irq to be absent > ARM: dts: imx6qdl: remove MSI irq line > > .../devicetree/bindings/pci/fsl,imx6q-pcie.txt | 8 ++++---- > arch/arm/boot/dts/imx6qdl.dtsi | 2 -- > drivers/pci/dwc/pci-imx6.c | 23 +++++++++++----------- > drivers/pci/dwc/pcie-designware-host.c | 4 ++-- > 4 files changed, 17 insertions(+), 20 deletions(-) > Lucas, Thank you for following up on this! I tested it with and without the third patch that removes msi from the dt thus with both an ath9k 802.11 device which only supports legacy interrupts and a Marvell sky2 device which supports msi as well as legacy interrupts and it works as expected: - without msi enabled in dts (default): both sky2 and ath9k work - with msi enabled in dt: sky2 works ath9k does not Tested-by: Tim Harvey <tharvey@xxxxxxxxxxxxx> Regards, Tim
