[B/OEM-B] [PATCH 1/1] PCI: Enable NVIDIA HDA controllers

Kai-Heng Feng kai.heng.feng at canonical.com
Fri Jul 12 06:34:30 UTC 2019

From: Lukas Wunner <lukas at wunner.de>

BugLink: https://bugs.launchpad.net/bugs/1836308

Many NVIDIA GPUs can be configured as either a single-function video device
or a multi-function device with video at function 0 and an HDA audio
controller at function 1.  The HDA controller can be enabled or disabled by
a bit in the function 0 config space.

Some BIOSes leave the HDA disabled, which means the HDMI connector from the
NVIDIA GPU may not work.  Sometimes the BIOS enables the HDA if an HDMI
cable is connected at boot time, but that doesn't handle hotplug cases.

Enable the HDA controller on device enumeration and resume and re-read the
header type, which tells us whether the GPU is a multi-function device.

This quirk is limited to NVIDIA PCI devices with the VGA Controller device
class.  This is expected to correspond to product configurations where the
NVIDIA GPU has connectors attached.  Other products where the device class
is 3D Controller are expected to correspond to configurations where the
NVIDIA GPU is dedicated (dGPU) and has no connectors.  See original post
(URL below) for more details.

This commit takes inspiration from an earlier patch by Daniel Drake.

Link: https://lore.kernel.org/r/20190708051744.24039-1-drake@endlessm.com
Link: https://devtalk.nvidia.com/default/topic/1024022
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75985
Signed-off-by: Lukas Wunner <lukas at wunner.de>
Signed-off-by: Daniel Drake <drake at endlessm.com>
[bhelgaas: commit log, log message, return early if already enabled]
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Cc: Aaron Plattner <aplattner at nvidia.com>
Cc: Peter Wu <peter at lekensteyn.nl>
Cc: Ilia Mirkin <imirkin at alum.mit.edu>
Cc: Karol Herbst <kherbst at redhat.com>
Cc: Maik Freudenberg <hhfeuer at gmx.de>
(backported from commit b678f90a1a6f8899542ea7bb190e268fb2d6ea0d git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git pci/misc)
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
 drivers/pci/quirks.c    | 30 ++++++++++++++++++++++++++++++
 include/linux/pci_ids.h |  1 +
 2 files changed, 31 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 0c5c1915b408..4c5ada1d43bf 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4896,3 +4896,33 @@ static void quirk_fsl_no_msi(struct pci_dev *pdev)
 		pdev->no_msi = 1;
+ * Enable the NVIDIA GPU integrated HDA controller if the BIOS left it
+ * disabled.  https://devtalk.nvidia.com/default/topic/1024022
+ */
+static void quirk_nvidia_hda(struct pci_dev *gpu)
+	u8 hdr_type;
+	u32 val;
+	/* There was no integrated HDA controller before MCP89 */
+	if (gpu->device < PCI_DEVICE_ID_NVIDIA_GEFORCE_320M)
+		return;
+	/* Bit 25 at offset 0x488 enables the HDA controller */
+	pci_read_config_dword(gpu, 0x488, &val);
+	if (val & BIT(25))
+		return;
+	pci_info(gpu, "Enabling HDA controller\n");
+	pci_write_config_dword(gpu, 0x488, val | BIT(25));
+	/* The GPU becomes a multi-function device when the HDA is enabled */
+	pci_read_config_byte(gpu, PCI_HEADER_TYPE, &hdr_type);
+	gpu->multifunction = !!(hdr_type & 0x80);
+			       PCI_BASE_CLASS_DISPLAY, 16, quirk_nvidia_hda);
+			       PCI_BASE_CLASS_DISPLAY, 16, quirk_nvidia_hda);
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index 0a6cfa98dfc1..5d8a3aa846c3 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -1327,6 +1327,7 @@
 #define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP77_IDE       0x0759
+#define PCI_DEVICE_ID_NVIDIA_GEFORCE_320M           0x08A0

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