Hi, Bjorn, On Tue, May 18, 2021 at 9:59 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > [+cc Rob, beginning of thread > https://lore.kernel.org/r/20210514080025.1828197-5-chenhuacai@xxxxxxxxxxx] > > On Sat, May 15, 2021 at 11:52:53AM +0800, Huacai Chen wrote: > > On Fri, May 14, 2021 at 10:52 PM Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> wrote: > > > 在 2021/5/14 16:00, Huacai Chen 写道: > > > > From: Jianmin Lv <lvjianmin@xxxxxxxxxxx> > > > > > > > > In LS7A, multifunction device use same pci PIN and different > > > > irq for different function, so fix it for standard pci PIN > > > > usage. > > > > > > Hmm, I'm unsure about this change. > > > The PCIe port, or PCI-to-PCI bridge on LS7A only have a single > > > upstream interrupt specified in DeviceTree, how can this quirk > > > work? > > > > LS7A will be shared by MIPS-based Loongson and LoongArch-based > > Loongson, LoongArch use ACPI rather than FDT, so this quirk is needed. > > Can you expand on this a little bit? > > Which DT binding are you referring to? Is it in the Linux source > tree? I referring to arch/mips/boot/dts/loongson/ls7a-pch.dtsi, it is already in Linux source tree. > > I think Linux reads Interrupt Pin for both FDT and ACPI systems, and > apparently that register contains the same value for all functions of > this multi-function device. > > The quirk will be applied for both FDT and ACPI systems, but it sounds > like you're saying this is needed *because* LoongArch uses ACPI. Jiaxun said that FDT system doesn't need this quirk, maybe he know more. Huacai > > Bjorn
