Messages in this thread | | | From | "Limonciello, Mario" <> | Subject | RE: [PATCH v3] PCI: Don't assume root ports from > 2015 are power manageable | Date | Wed, 24 May 2023 16:16:20 +0000 |
| |
[AMD Official Use Only - General]
> -----Original Message----- > From: Lukas Wunner <lukas@wunner.de> > Sent: Wednesday, May 24, 2023 10:45 AM > To: Limonciello, Mario <Mario.Limonciello@amd.com> > Cc: Bjorn Helgaas <bhelgaas@google.com>; Mika Westerberg > <mika.westerberg@linux.intel.com>; Rafael J . Wysocki <rafael@kernel.org>; > linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; S-k, Shyam-sundar > <Shyam-sundar.S-k@amd.com>; Natikar, Basavaraj > <Basavaraj.Natikar@amd.com>; Deucher, Alexander > <Alexander.Deucher@amd.com>; linux-pm@vger.kernel.org; Iain Lane > <iain@orangesquash.org.uk> > Subject: Re: [PATCH v3] PCI: Don't assume root ports from > 2015 are power > manageable > > On Wed, May 24, 2023 at 10:21:36AM -0500, Mario Limonciello wrote: > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -2976,6 +2976,9 @@ bool pci_bridge_d3_possible(struct pci_dev > *bridge) > > > > switch (pci_pcie_type(bridge)) { > > case PCI_EXP_TYPE_ROOT_PORT: > > + if (!platform_pci_power_manageable(bridge)) > > + return false; > > + fallthrough; > > case PCI_EXP_TYPE_UPSTREAM: > > case PCI_EXP_TYPE_DOWNSTREAM: > > if (pci_bridge_d3_disable) > > This will exempt the Root Ports from pcie_port_pm=force. > Not sure if that's desirable.
Right; It will only exempt root ports from pcie_port_pm=force if they aren't power manageable.
If it's still desirable to let pcie_port_pm=force work on these I think it's worth refactoring the function otherwise it's going to be a nested if that matches the same variable as the switch.
Something like this:
bool pci_bridge_d3_possible(struct pci_dev *bridge) { if (!pci_is_pcie(bridge)) return false;
switch (pci_pcie_type(bridge)) { case PCI_EXP_TYPE_ROOT_PORT: case PCI_EXP_TYPE_UPSTREAM: case PCI_EXP_TYPE_DOWNSTREAM: break; default: return false; }
if (pci_bridge_d3_disable) return false;
/* * Hotplug ports handled by firmware in System Management Mode * may not be put into D3 by the OS (Thunderbolt on non-Macs). */ if (bridge->is_hotplug_bridge && !pciehp_is_native(bridge)) return false;
if (pci_bridge_d3_force) return true;
/* Even the oldest 2010 Thunderbolt controller supports D3. */ if (bridge->is_thunderbolt) return true;
/* Platform might know better if the bridge supports D3 */ if (platform_pci_bridge_d3(bridge)) return true;
/* * Hotplug ports handled natively by the OS were not validated * by vendors for runtime D3 at least until 2018 because there * was no OS support. */ if (bridge->is_hotplug_bridge) return false;
if (dmi_check_system(bridge_d3_blacklist)) return false;
/* * It should be safe to put PCIe ports from 2015 or newer * to D3. */ if (dmi_get_bios_year() >= 2015) return true;
return false; }
Then the check I'm proposing can injected anywhere after the force like this:
if (pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT && !platform_pci_power_manageable(bridge))) return false;
| |