This says it's a resend, but I don't see a previous posting; maybe it was HTML and rejected by the mailing list? On Mon, Apr 15, 2019 at 04:59:03PM +0300, Alexander Fomichev wrote: > PLX switches have an issue that their internal registers become inaccessible > when runtime PM is enabled. Therefore PLX service tools can't communicate > with the hardware. A kernel option "pcie_port_pm=off" can be used as a > workaround. But it affects all the devices. > So this solution is to add PLX switch devices to the quirk list for > disabling runtime PM only for them. I assume the problem is actually that the config space registers are inaccessible when the device is in D3hot? I think config space access is supposed to work when a device is in D3hot (see PCIe r4.0, sec 5.3.1.4). If it doesn't work, wouldn't that mean that we couldn't even bring the device *out* of D3hot, since that requires a config write? If this is really the problem, it'd be nice to identify this specifically instead of piggy-backing on the "is_hotplug_bridge" thing, which might be coincidentally related, but also carries other meanings. > --- > drivers/pci/quirks.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index a59ad09..8ea99aa 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -2923,6 +2923,17 @@ static void quirk_hotplug_bridge(struct pci_dev *dev) > dev->is_hotplug_bridge = 1; > } > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_HINT, 0x0020, quirk_hotplug_bridge); > +/* > + * Disable runtime PM for PLX Draco (1,2), Capella (1,2) series PCIe switches > + * to prevent service tools from failing to access hardware registers. > + */ > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x8712, quirk_hotplug_bridge); > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x8733, quirk_hotplug_bridge); > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x8734, quirk_hotplug_bridge); > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x8780, quirk_hotplug_bridge); > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x8796, quirk_hotplug_bridge); > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x9781, quirk_hotplug_bridge); > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x9797, quirk_hotplug_bridge); > > /* > * This is a quirk for the Ricoh MMC controller found as a part of some > -- > 2.7.4
