On 7/3/2025 8:39 PM, Vivek.Pernamitta@quicinc.com wrote:
> From: Vivek Pernamitta <quic_vpernami@quicinc.com>
>
> In SRIOV enabled devices, the VF DEVICE/VENDOR ID register returns FFFFh
> when read (PCIe SRIOV spec-3.4.1.1). Therefore, read the PCIe
> SUBSYSTEM_VENDOR_ID to check if the device is active.
>
Reviewed-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
- Krishna Chaitanya.
> Signed-off-by: Vivek Pernamitta <quic_vpernami@quicinc.com>
> ---
> drivers/bus/mhi/host/pci_generic.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
> index 22de02c26ceb946fb618d962ac8882d2db1be6b4..938f37d306a18b9a47f302df85697f837c225f0d 100644
> --- a/drivers/bus/mhi/host/pci_generic.c
> +++ b/drivers/bus/mhi/host/pci_generic.c
> @@ -1025,8 +1025,10 @@ static bool mhi_pci_is_alive(struct mhi_controller *mhi_cntrl)
> struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev);
> u16 vendor = 0;
>
> - if (pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor))
> - return false;
> + if (pdev->is_virtfn)
> + pci_read_config_word(pdev, PCI_SUBSYSTEM_VENDOR_ID, &vendor);
> + else
> + pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor);
>
> if (vendor == (u16) ~0 || vendor == 0)
> return false;
>