Re: [PATCH v5 0/3] PCI: Restrict pci transactions after pci suspend

Bjorn Helgaas
2022-08-24T20:30:01Z

On Wed, Aug 03, 2022 at 04:58:51PM +0530, Krishna chaitanya chundru wrote:
> If the endpoint device state is D0 and irq's are not freed, then
> kernel try to mask interrupts in system suspend path by writing in to
> the vector table (for MSIX interrupts) and config space (for MSI's).

If clocks are being turned off while the PCI core is still accessing
the device, I think that means qcom suspend is not implemented
correctly.

> These transactions are initiated in the pm suspend after pcie clocks got
> disabled as part of platform driver pm suspend call. Due to it, these
> transactions are resulting in un-clocked access and eventually to crashes.
>
> So added a logic in qcom driver to restrict these unclocked access.
> And updated the logic to check the link state before masking
> or unmasking the interrupts.
>
> And some devices are taking time to settle the link in L1ss, so added a
> retry logic in the suspend ops.
>
> Krishna chaitanya chundru (3):
> PCI: qcom: Add system PM support
> PCI: qcom: Restrict pci transactions after pci suspend
> PCI: qcom: Add retry logic for link to be stable in L1ss
>
> drivers/pci/controller/dwc/pcie-designware-host.c | 14 ++-
> drivers/pci/controller/dwc/pcie-qcom.c | 117 +++++++++++++++++++++-
> 2 files changed, 127 insertions(+), 4 deletions(-)
>
> --
> 2.7.4
>