On Fri, Oct 2, 2020 at 7:17 AM Lukas Wunner <lukas@xxxxxxxxx> wrote: > > Recent laptops with dual AMD GPUs fail to suspend the discrete GPU, thus > causing lockups on system sleep and high power consumption at runtime. > The discrete GPU would normally be suspended to D3cold by turning off > ACPI _PR3 Power Resources of the Root Port above the GPU. > > However on affected systems, the Root Port is hotplug-capable and > pci_bridge_d3_possible() only allows hotplug ports to go to D3 if they > belong to a Thunderbolt device or if the Root Port possesses a > "HotPlugSupportInD3" ACPI property. Neither is the case on affected > laptops. The reason for whitelisting only specific, known to work > hotplug ports for D3 is that there have been reports of SkyLake Xeon-SP > systems raising Hardware Error NMIs upon suspending their hotplug ports: > https://lore.kernel.org/linux-pci/20170503180426.GA4058@otc-nc-03/ > > But if a hotplug port is power manageable by ACPI (as can be detected > through presence of Power Resources and corresponding _PS0 and _PS3 > methods) then it ought to be safe to suspend it to D3. To this end, > amend acpi_pci_bridge_d3() to whitelist such ports for D3. > > Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1222 > Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1252 > Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1304 > Reported-and-tested-by: Arthur Borsboom <arthurborsboom@xxxxxxxxx> > Reported-and-tested-by: matoro <matoro@xxxxxxxxxx> > Reported-by: Aaron Zakhrov <aaron.zakhrov@xxxxxxxxx> > Reported-by: Michal Rostecki <mrostecki@xxxxxxxx> > Reported-by: Shai Coleman <git@xxxxxxxxxxxxxxx> > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Cc: Alex Deucher <alexander.deucher@xxxxxxx> > Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > --- > drivers/pci/pci-acpi.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c > index d5869a0..d9aa551 100644 > --- a/drivers/pci/pci-acpi.c > +++ b/drivers/pci/pci-acpi.c > @@ -944,6 +944,16 @@ static bool acpi_pci_bridge_d3(struct pci_dev *dev) > if (!dev->is_hotplug_bridge) > return false; > > + /* Assume D3 support if the bridge is power-manageable by ACPI. */ > + adev = ACPI_COMPANION(&dev->dev); > + if (!adev && !pci_dev_is_added(dev)) { > + adev = acpi_pci_find_companion(&dev->dev); > + ACPI_COMPANION_SET(&dev->dev, adev); > + } > + > + if (adev && acpi_device_power_manageable(adev)) > + return true; > + > /* > * Look for a special _DSD property for the root port and if it > * is set we know the hierarchy behind it supports D3 just fine. > -- I'm going to apply this patch for 5.10 unless Bjorn would rather route it through the PCI tree. Thanks!
