On Fri, Apr 01, 2022 at 07:32:58AM -0500, Limonciello, Mario wrote: > On 4/1/2022 07:29, Bjorn Helgaas wrote: > > On Fri, Apr 01, 2022 at 01:44:42PM +0200, Rafael J. Wysocki wrote: > > > On Fri, Apr 1, 2022 at 5:40 AM Mario Limonciello > > > <mario.limonciello@xxxxxxx> wrote: > > > > > > > > acpi_pci_bridge_d3(dev) returns "true" if "dev" is a hotplug bridge > > > > that can handle hotplug events while in D3. Previously this meant: > > > > > > > > 1) "dev" has a _PS0 or _PR0 method, or > > > > > > > > 2) The Root Port above "dev" has a _DSD with a "HotPlugSupportInD3" > > > > property with value 1. > > > > > > > > This did not consider_S0W, which tells us the deepest D-state from > > > > which a device can wake itself (ACPI v6.4, sec 7.3.20). > > > > > > > > On some platforms, e.g., AMD Yellow Carp, firmware may supply > > > > "HotPlugSupportInD3" even though the platform does not supply power > > > > resources through _PRW and _S0W tells us the device cannot wake from > > > > > > More importantly, it doesn't supply a wakeup GPE number through _PRW, > > > so from the ACPI perspective the bridge has no way of generating > > > wakeup signals. > > > > Perfect, thanks. That's the missing piece about _PRW. > > > > > > D3hot. With the previous code, these devices could be put in D3hot > > > > and hotplugged devices would not be recognized without manually > > > > rescanning. > > > > > > > > If _S0W exists and says the Root Port cannot wake itself from D3hot, > > > > return "false" to indicate that "dev" cannot handle hotplug events > > > > while in D3. > > > > > > > > 1) "dev" has a _PS0 or _PR0 method, or > > > > > > > > 2a) The Root Port above "dev" has _PRW and > > > > > > > > 2b) If the Root Port above "dev" has _S0W, it can wake from D3hot or > > > > D3cold and > > > > > > > > 2c) The Root Port above "dev" has a _DSD with a > > > > "HotPlugSupportInD3" property with value 1. > > > > > > > > Windows 10 and Windows 11 both will prevent the bridge from going in D3 > > > > when the firmware is configured this way and this change aligns the > > > > handling of the situation to be the same. > > > > > > > > Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fuefi.org%2Fhtmlspecs%2FACPI_Spec_6_4_html%2F07_Power_and_Performance_Mgmt%2Fdevice-power-management-objects.html%3Fhighlight%3Ds0w%23s0w-s0-device-wake-state&data=04%7C01%7Cmario.limonciello%40amd.com%7Cc8ff8ac0568049a166bd08da13db41f3%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637844129686586061%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=bjd5NnFaGslXcSVvShZMRHzuedEx8VgGnEnCGlWZ%2F2Q%3D&reserved=0 > > > > Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fwindows-hardware%2Fdrivers%2Fpci%2Fdsd-for-pcie-root-ports%23identifying-pcie-root-ports-supporting-hot-plug-in-d3&data=04%7C01%7Cmario.limonciello%40amd.com%7Cc8ff8ac0568049a166bd08da13db41f3%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637844129686586061%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=r11UKOwL6SvGv4VCxaDyH0k15dsJib%2BJvRCS2MRobUQ%3D&reserved=0 > > > > Fixes: 26ad34d510a87 ("PCI / ACPI: Whitelist D3 for more PCIe hotplug ports") > > > > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> > > > > -- > > > > v5->v6: > > > > * Re-order checks to only check for _DSD if necessary as suggested by Bjorn. > > > > * Adjust commit message wording > > > > * Drop rewording comment patch, just apply it while moving text to avoid > > > > ping-ponging the same lines in the commits. > > > > v4-v5: > > > > * Don't fail if _S0W is missing > > > > --- > > > > drivers/pci/pci-acpi.c | 25 +++++++++++++++++++------ > > > > 1 file changed, 19 insertions(+), 6 deletions(-) > > > > > > > > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c > > > > index 1f15ab7eabf8..5ab797e2709d 100644 > > > > --- a/drivers/pci/pci-acpi.c > > > > +++ b/drivers/pci/pci-acpi.c > > > > @@ -976,7 +976,9 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev) > > > > { > > > > const union acpi_object *obj; > > > > struct acpi_device *adev; > > > > + unsigned long long state; > > > > struct pci_dev *rpdev; > > > > + acpi_status status; > > > > > > > > if (acpi_pci_disabled || !dev->is_hotplug_bridge) > > > > return false; > > > > @@ -985,12 +987,6 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev) > > > > if (acpi_pci_power_manageable(dev)) > > > > return true; > > > > > > > > - /* > > > > - * The ACPI firmware will provide the device-specific properties through > > > > - * _DSD configuration object. Look for the 'HotPlugSupportInD3' property > > > > - * for the root port and if it is set we know the hierarchy behind it > > > > - * supports D3 just fine. > > > > - */ > > > > rpdev = pcie_find_root_port(dev); > > > > if (!rpdev) > > > > return false; > > > > @@ -999,6 +995,23 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev) > > > > if (!adev) > > > > return false; > > > > > > > > + /* > > > > + * If the bridge can't wake from D3hot, it can't signal hotplug > > > > + * events in D3hot. > > > > > > I would say "If the bridge cannot signal wakeup signals at all, it > > > cannot signal hotplug events from low-power states including D3hot and > > > D3cold." > > > > > > With the two above remarks addressed, please feel free to add > > > > > > Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > Great, thanks! > > Bjorn, > > Please let me know if you want me to send up a v7 with the minor remark > updates, or if you can just fix those up while committing. Fixing those up right now. I'll post the updates shortly so you can make sure I didn't make it worse. Bjorn
