[RFC PATCH] PCI: Extend D3hot delay for NVIDIA HDA controllers

Alex Williamson
2023-03-28T23:00:21Z

Assignment of NVIDIA Ampere-based GPUs have seen a regression since the
below referenced commit, where the reduced D3hot transition delay appears
to introduce a small window where a D3hot->D0 transition followed by a bus
reset can wedge the device. The entire device is subsequently unavailable,
returning -1 on config space read and is unrecoverable without a host reset.

This has been observed with RTX A2000 and A5000 GPU and audio functions
assigned to a Windows VM, where shutdown of the VM places the devices in
D3hot prior to vfio-pci performing a bus reset when userspace releases the
devices. The issue has roughly a 2-3% chance of occurring per shutdown.

Restoring the HDA controller d3hot_delay to the effective value before the
below commit has been shown to resolve the issue.

I'm looking for input from NVIDIA whether this issue is unique to
Ampere-based HDA controllers or should be assumed to linger in both older
and newer controllers as well. Currently we've not been able to reproduce
the issue other than on Ampere HDA controllers, however the implementation
here includes all NVIDIA HDA controllers based on PCI vendor and device
class.

If we were to limit the quirk to Ampere HDA controllers, I think that would
include:

1aef GA102 High Definition Audio Controller
228b GA104 High Definition Audio Controller
228e GA106 High Definition Audio Controller

Cc: Abhishek Sahu <abhsahu@nvidia.com>
Cc: Tarun Gupta <targupta@nvidia.com>
Fixes: 3e347969a577 ("PCI/PM: Reduce D3hot delay with usleep_range()")
Reported-by: Zhiyi Guo <zhguo@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
drivers/pci/quirks.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 44cab813bf95..f4e2a88729fd 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1939,6 +1939,19 @@ static void quirk_radeon_pm(struct pci_dev *dev)
}
DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x6741, quirk_radeon_pm);

+/*
+ * NVIDIA Ampere-based HDA controllers can wedge the whole device if a bus
+ * reset is performed too soon after transition to D0, extend d3hot_delay
+ * to previous effective default for all NVIDIA HDA controllers.
+ */
+static void quirk_nvidia_hda_pm(struct pci_dev *dev)
+{
+ quirk_d3hot_delay(dev, 20);
+}
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
+ PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8,
+ quirk_nvidia_hda_pm);
+
/*
* Ryzen5/7 XHCI controllers fail upon resume from runtime suspend or s2idle.
* https://bugzilla.kernel.org/show_bug.cgi?id=205587