Re: [PATCH 3/8] PCI: qcom: Do not advertise hotplug capability for IPs v2.7.0 and v1.9.0

[Dmitry Baryshkov]

On 06/05/2023 10:31, Manivannan Sadhasivam wrote:
> SoCs making use of Qcom PCIe controller IPs v2.7.0 and v1.9.0 do not
> support hotplug functionality. But the hotplug capability bit is set by
> default in the hardware. This causes the kernel PCI core to register
> hotplug service for the controller and send hotplug commands to it. But
> those commands will timeout generating messages as below during boot and
> suspend/resume.
>
> [    5.782159] pcieport 0001:00:00.0: pciehp: Timeout on hotplug command 0x03c0 (issued 2020 msec ago)
> [    5.810161] pcieport 0001:00:00.0: pciehp: Timeout on hotplug command 0x03c0 (issued 2048 msec ago)
> [    7.838162] pcieport 0001:00:00.0: pciehp: Timeout on hotplug command 0x07c0 (issued 2020 msec ago)
> [    7.870159] pcieport 0001:00:00.0: pciehp: Timeout on hotplug command 0x07c0 (issued 2052 msec ago)
>
> This not only spams the console output but also induces a delay of a
> couple of seconds. To fix this issue, let's clear the HPC bit in
> PCI_EXP_SLTCAP register as a part of the post init sequence to not
> advertise the hotplug capability for the controller.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> ---
>   drivers/pci/controller/dwc/pcie-qcom.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxx>

--
With best wishes
Dmitry