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From:   Shanker Donthineni <sdonthineni@nvidia.com>
To:     Alex Williamson <alex.williamson@redhat.com>
CC:     Bjorn Helgaas <bhelgaas@google.com>, <linux-pci@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, Sinan Kaya <okaya@kernel.org>,
        Vikram Sethi <vsethi@nvidia.com>,
        Amey Narkhede <ameynarkhede03@gmail.com>,
        "Shanker Donthineni" <sdonthineni@nvidia.com>
Subject: [PATCH v4 2/2] PCI: Enable NO_BUS_RESET quirk for Nvidia GPUs
Date:   Wed, 28 Apr 2021 19:49:07 -0500
Message-ID: <20210429004907.29044-2-sdonthineni@nvidia.com>
In-Reply-To: <20210429004907.29044-1-sdonthineni@nvidia.com>
References: <20210429004907.29044-1-sdonthineni@nvidia.com>
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On select platforms, some Nvidia GPU devices do not work with SBR.
Triggering SBR would leave the device inoperable for the current
system boot. It requires a system hard-reboot to get the GPU device
back to normal operating condition post-SBR. For the affected
devices, enable NO_BUS_RESET quirk to fix the issue.

This issue will be fixed in the next generation of hardware.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
---
Changes since v1:
 - Split patch into 2, code for handling _RST and SBR specific quirk
 - The RST based reset is called as a first-class mechanism in the reset code path

 drivers/pci/quirks.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 8f47d139c381..e1216a8165df 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3910,6 +3910,18 @@ static int delay_250ms_after_flr(struct pci_dev *dev, int probe)
 	return 0;
 }
 
+/*
+ * Some Nvidia GPU devices do not work with bus reset, SBR needs to be
+ * prevented for those affected devices.
+ */
+static void quirk_nvidia_no_bus_reset(struct pci_dev *dev)
+{
+	if ((dev->device & 0xffc0) == 0x2340)
+		dev->dev_flags |= PCI_DEV_FLAGS_NO_BUS_RESET;
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
+			 quirk_nvidia_no_bus_reset);
+
 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 },
-- 
2.17.1