From 51ba09452d11b17248d80c740c2fd14c9fdc2c99 Mon Sep 17 00:00:00 2001
From: Alex Williamson <alex.williamson@redhat.com>
Date: Thu, 9 Aug 2018 14:04:31 -0600
Subject: [PATCH] PCI: Delay after FLR of Intel DC P3700 NVMe
Git-commit: 51ba09452d11b17248d80c740c2fd14c9fdc2c99
Patch-mainline: v4.19-rc1
References: bsc#1120058
Add a device-specific reset for Intel DC P3700 NVMe device which exhibits a
timeout failure in drivers waiting for the ready status to update after
NVMe enable if the driver interacts with the device too soon after FLR. As
this has been observed in device assignment scenarios, resolve this with a
device-specific reset quirk to add an additional, heuristically determined,
delay after the FLR completes.
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1592654
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/pci/quirks.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index e249676fbf04..deb051583eda 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3746,6 +3746,27 @@ static int nvme_disable_and_flr(struct pci_dev *dev, int probe)
return 0;
}
+/*
+ * Intel DC P3700 NVMe controller will timeout waiting for ready status
+ * to change after NVMe enable if the driver starts interacting with the
+ * device too soon after FLR. A 250ms delay after FLR has heuristically
+ * proven to produce reliably working results for device assignment cases.
+ */
+static int delay_250ms_after_flr(struct pci_dev *dev, int probe)
+{
+ if (!pcie_has_flr(dev))
+ return -ENOTTY;
+
+ if (probe)
+ return 0;
+
+ pcie_flr(dev);
+
+ msleep(250);
+
+ return 0;
+}
+
static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF,
reset_intel_82599_sfp_virtfn },
@@ -3754,6 +3775,7 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IVB_M2_VGA,
reset_ivb_igd },
{ PCI_VENDOR_ID_SAMSUNG, 0xa804, nvme_disable_and_flr },
+ { PCI_VENDOR_ID_INTEL, 0x0953, delay_250ms_after_flr },
{ PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID,
reset_chelsio_generic_dev },
{ 0 }
--
2.20.1