Re: [PATCH] PCI: dw-rockchip: Enable INTx affinity support

[Thomas Gleixner <tglx@kernel.org>]

On Mon, Oct 19 2026 at 08:25, Shawn Lin wrote:
> 在 2026/10/19 星期一 4:04, Thomas Gleixner 写道:
>> On Sun, Oct 18 2026 at 10:05, Manivannan Sadhasivam wrote:
>>> On Tue, Sep 29, 2026 at 02:54:58PM +0800, Shawn Lin wrote:
>>>> Leverage the interrupt redirection infrastructure to enable CPU
>>>> affinity support for the legacy INTx interrupts. The INTx virqs are
>>>> demultiplexed by the chained handler of the "legacy" interrupt, whose
>>>> affinity cannot be changed, so affinity control for the INTx virqs is
>>>> achieved by redirecting the handler to run in IRQ work context on the
>>>> target CPU.
>>>>
>>>> Mask the INTx source in .irq_pre_redirect() before the handler is
>>>> redirected: the legacy interrupt is level triggered, so an unmasked
>>>> line would keep re-firing the chained interrupt until the redirected
>>>> handler runs.
>>>>
>>>> Same approach as the DesignWare core, commit eaf290c404f7c39f2 ("PCI:
>>>> dwc: Enable MSI affinity support").
>>>>
>>>> Test was done on RK3588 EVB1 board with an NVMe with pci=nomsi
>>>> parameter. The /proc/interrupts columns are trimmed for brevity.
>>>>
>>>>    # cat /proc/interrupts | grep INTx
>>>>    51:  137 0 0 0 0 0 0 0 INTx 0 Edge PCIe PME, nvme0q0, nvme0q1
>>>>    # echo 10 > /proc/irq/51/smp_affinity
>>>>    # dd if=/dev/nvme0n1p1 of=/dev/null bs=1M count=200
>>>>    200+0 records in
>>>>    200+0 records out
>>>>    209715200 bytes (210 MB, 200 MiB) copied, 0.182021 s, 1.2 GB/s
>>>>    # cat /proc/interrupts | grep INTx
>>>>    51:  137 0 0 0 946 0 0 0 INTx 0 Edge PCIe PME, nvme0q0, nvme0q1
>>>>
>>>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>>>
>>> I'd like to get an Ack from Thomas for this patch since I'm not an irqchip
>>> expert to decipher whether this patch is valid or not.

Yes, the patch is valid and uses the redirection mechanism correctly.

Acked-by: Thomas Gleixner <tglx@kernel.org>