On Wed, Jun 25, 2025, Bjorn Helgaas wrote:
> On Tue, Jun 24, 2025 at 10:16:37AM -0700, Sean Christopherson wrote:
> > +void pci_pm_init(struct pci_dev *dev)
> > +{
> > + u16 status;
> > +
> > + device_enable_async_suspend(&dev->dev);
> > + dev->wakeup_prepared = false;
> > +
> > + dev->pm_cap = 0;
> > + dev->pme_support = 0;
> > +
> > + /*
> > + * Note, support for the PCI PM spec is optional for legacy PCI devices
> > + * and for VFs. Continue on even if no PM capabilities are supported.
> > + */
> > + __pci_pm_init(dev);
> >
> > pci_read_config_word(dev, PCI_STATUS, &status);
> > if (status & PCI_STATUS_IMM_READY)
> > dev->imm_ready = 1;
>
> I would rather just move this PCI_STATUS read to somewhere else. I
> don't think there's a great place to put it. We could put it in
> set_pcie_port_type(), which is sort of a grab bag of PCIe-related
> things.
>
> I don't know if it's necessarily even a PCIe-specific thing, but it
> would be unexpected if somebody made a conventional PCI device that
> set it, since the bit was reserved (and should be zero) in PCI r3.0
> and defined in PCIe r4.0.
>
> Maybe we should put it in pci_setup_device() close to where we call
> pci_intx_mask_broken()?
Any reason not to throw it in pci_init_capabilities()? That has the advantage
of minimizing the travel distance, e.g. to avoid introducing a goof similar to
what happened with 4d4c10f763d7 ("PCI: Explicitly put devices into D0 when initializing").
E.g. something silly like this? Or maybe pci_misc_init() or so?
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 9e42090fb108..4a1ba5c017cd 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3205,7 +3205,6 @@ void pci_pm_power_up_and_verify_state(struct pci_dev *pci_dev)
void pci_pm_init(struct pci_dev *dev)
{
int pm;
- u16 status;
u16 pmc;
device_enable_async_suspend(&dev->dev);
@@ -3266,9 +3265,6 @@ void pci_pm_init(struct pci_dev *dev)
pci_pme_active(dev, false);
}
- pci_read_config_word(dev, PCI_STATUS, &status);
- if (status & PCI_STATUS_IMM_READY)
- dev->imm_ready = 1;
poweron:
pci_pm_power_up_and_verify_state(dev);
pm_runtime_forbid(&dev->dev);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4b8693ec9e4c..d33b8af37247 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2595,6 +2595,15 @@ void pcie_report_downtraining(struct pci_dev *dev)
__pcie_print_link_status(dev, false);
}
+static void pci_imm_ready_init(struct pci_dev *dev)
+{
+ u16 status;
+
+ pci_read_config_word(dev, PCI_STATUS, &status);
+ if (status & PCI_STATUS_IMM_READY)
+ dev->imm_ready = 1;
+}
+
static void pci_init_capabilities(struct pci_dev *dev)
{
pci_ea_init(dev); /* Enhanced Allocation */
@@ -2604,6 +2613,7 @@ static void pci_init_capabilities(struct pci_dev *dev)
/* Buffers for saving PCIe and PCI-X capabilities */
pci_allocate_cap_save_buffers(dev);
+ pci_imm_ready_init(dev); /* Immediate Ready */
pci_pm_init(dev); /* Power Management */
pci_vpd_init(dev); /* Vital Product Data */
pci_configure_ari(dev); /* Alternative Routing-ID Forwarding */
