On 5/3/21 5:42 PM, Bjorn Helgaas wrote:
> Obviously _RST only works for built-in devices, since there's no AML
> for plug-in devices, right? So if there's a plug-in card with this
> GPU, neither SBR nor _RST will work?
These are not plug-in PCIe GPU cards, will exist on upcoming server
baseboards. ACPI-reset should wok for plug-in devices as well as long
as firmware has _RST method defined in ACPI-device associated with
the PCIe hot-plug slot.
I've verified PCIe plug-in feature using SYSFS interface.
1) Remove device using sysfs interface
root@test:/sys/bus/pci# echo 1 > devices/0005:01:00.0/remove
root@test:/sys/bus/pci# lspci -s 0005:01:00.0
2) Rescan PCI bus using sysfs interface
root@test:/sys/bus/pci# echo 1 > devices/0005:00:00.0/rescan
root@test:/sys/bus/pci# lspci -s 0005:01:00.0
0005:01:00.0 3D controller: NVIDIA Corporation Device 2341 (rev a1)
3) List current reset methods
root@jetson:/sys/bus/pci# cat devices/0005:01:00.0/reset_method
acpi,flr
Example AML code:
// Device definition for slot/devfn
Device(GPU0) {
Name(_ADR,0x00000000)
Method (_RST, 0)
{
printf("Entering ACPI _RST method")
// RESET code
printf("Exiting ACPI _RST method")
}
}
4) Issue device reset from the userspace
root@test:/sys/bus/pci# echo 1 > devices/0005:01:00.0/reset
dmesg:
[ 6156.426303] ACPI Debug: "Entering PCI9 _RST method"
[ 6156.427007] ACPI Debug: "Exiting PCI9 _RST method"
> I'm wondering if we should log something to dmesg in
> quirk_no_bus_reset(), quirk_no_pm_reset(), quirk_no_flr(), etc., just
> so we have a hint about the fact that resets won't work quite as
> expected on these devices.
Yes, it would be very useful to know what PCI quirks were applied during boot.
Should I create a separate patch for adding pci_info() or include as part of this
patch?
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3556,6 +3556,7 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_MELLANOX, PCI_ANY_ID,
static void quirk_no_bus_reset(struct pci_dev *dev)
{
dev->dev_flags |= PCI_DEV_FLAGS_NO_BUS_RESET;
+pci_info(dev, "Applied NO_BUS_RESET quirk\n");
}
/*
@@ -3598,6 +3599,7 @@ static void quirk_no_pm_reset(struct pci_dev *dev)
*/
if (!pci_is_root_bus(dev->bus))
dev->dev_flags |= PCI_DEV_FLAGS_NO_PM_RESET;
+pci_info(dev, "Applied NO_PM_RESET quirk\n");
}
/*
@@ -5138,6 +5140,7 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x443, quirk_intel_qat_vf_cap);
static void quirk_no_flr(struct pci_dev *dev)
{
dev->dev_flags |= PCI_DEV_FLAGS_NO_FLR_RESET;
+pci_info(dev, "Applied NO_FLR_RESET quirk\n");
}
