Re: [PATCH] pci: dwc: Clear MSI interrupt status after it is handled

From: Bjorn Helgaas
Date: Tue Aug 22 2017 - 16:51:42 EST


On Thu, Aug 10, 2017 at 04:54:55PM +0530, Faiz Abbas wrote:
> If the interrupt status is cleared before it is handled, it is possible
> that another interrupt will trigger while servicing the previous one.
> This is causing timeouts in some wireless lan cards which use pcie.
> Therefore, clear MSI interrupt status after it gets serviced instead
> of before calling generic_handler.
>
> Signed-off-by: Faiz Abbas <faiz_abbas@xxxxxx>

Applied with Joao's ack to pci/host-designware for v4.14, thanks!

> ---
> drivers/pci/dwc/pcie-designware-host.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
> index 28ed32b..78b2584 100644
> --- a/drivers/pci/dwc/pcie-designware-host.c
> +++ b/drivers/pci/dwc/pcie-designware-host.c
> @@ -71,9 +71,9 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
> while ((pos = find_next_bit((unsigned long *) &val, 32,
> pos)) != 32) {
> irq = irq_find_mapping(pp->irq_domain, i * 32 + pos);
> + generic_handle_irq(irq);
> dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12,
> 4, 1 << pos);
> - generic_handle_irq(irq);
> pos++;
> }
> }
> --
> 2.7.4
>