Daniel Drake
2019-Jul-08 05:17 UTC
[Nouveau] [PATCH v2] PCI: Expose hidden NVIDIA HDA controllers
From: Lukas Wunner <lukas at wunner.de>
The integrated HDA controller on Nvidia GPUs can be hidden with a bit in
the GPU's config space. Information about this scheme was provided by
NVIDIA on their forums.
Many laptops now ship with this device hidden, meaning that Linux users
of affected platforms (where the HDMI connector comes off the NVIDIA GPU)
cannot use HDMI audio functionality.
Some platforms have ACPI DSDT code that will make the device visible if
the HDMI cable was connected at boot time, but this does not handle the
hotplug case, and this limitation has also been confirmed under Windows.
Avoid this issue by exposing the HDMI audio device on device enumeration
and resume.
The GPU and HDA controller are two functions of the same PCI device
(VGA class device on function 0 and audio device on function 1).
The multifunction flag in the GPU's Header Type register is cleared when
the HDA controller is hidden and set if it's exposed, so reread the flag
after exposing the HDA.
According to Ilia Mirkin, the HDA controller is only present on GPUs with
PCI ID values from MCP89's onwards, so do not touch config space on older
GPUs.
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.
It's sensible to avoid exposing the HDA controller on dGPU setups,
especially because we've seen cases where the PCI BARs are not set
up correctly by the platform in this case, causing Linux to log
errors if the device is visible. This assumption of device class
accurately corresponding to product configuration is true for 6 of 6
laptops recently checked at the Endless lab, and there are also signs of
agreement checking the data from 74 previously tested products, however
Ilia Mirkin comments that he's seen cases where it is not true. Anyway, it
looks like this quirk should fix audio support for the majority of
affected users.
This commit takes inspiration from an earlier patch by Daniel Drake.
Link: https://devtalk.nvidia.com/default/topic/1024022
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75985
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>
Signed-off-by: Lukas Wunner <lukas at wunner.de>
Signed-off-by: Daniel Drake <drake at endlessm.com>
---
Notes:
v2:
- Mention in commit message that the ACPI code that controls this bit
is insufficient (also confirmed on Windows on the buglink)
- Tweak commit message to clarify the MCP89 comparison, thanks to Ilia
drivers/pci/quirks.c | 28 ++++++++++++++++++++++++++++
include/linux/pci_ids.h | 1 +
2 files changed, 29 insertions(+)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 0f16acc323c6..52046b517e2e 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4971,6 +4971,34 @@ DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_AMD,
PCI_ANY_ID,
DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda);
+/*
+ * Many laptop BIOSes hide the integrated HDA controller on NVIDIA GPUs
+ * via a special bit. This prevents Linux from seeing and using it.
+ * Unhide it here.
+ * 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 hides or exposes the HDA controller */
+ pci_read_config_dword(gpu, 0x488, &val);
+ pci_write_config_dword(gpu, 0x488, val | BIT(25));
+
+ /* the GPU becomes a multifunction device when the HDA is exposed */
+ pci_read_config_byte(gpu, PCI_HEADER_TYPE, &hdr_type);
+ gpu->multifunction = !!(hdr_type & BIT(7));
+}
+DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
+ PCI_BASE_CLASS_DISPLAY, 16, quirk_nvidia_hda);
+DECLARE_PCI_FIXUP_CLASS_RESUME_EARLY(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
+ PCI_BASE_CLASS_DISPLAY, 16, quirk_nvidia_hda);
+
/*
* Some IDT switches incorrectly flag an ACS Source Validation error on
* completions for config read requests even though PCIe r4.0, sec
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index 70e86148cb1e..66898463b81f 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -1336,6 +1336,7 @@
#define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS 0x0752
#define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP77_IDE 0x0759
#define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP73_SMBUS 0x07D8
+#define PCI_DEVICE_ID_NVIDIA_GEFORCE_320M 0x08A0
#define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS 0x0AA2
#define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP89_SATA 0x0D85
--
2.20.1
Bjorn Helgaas
2019-Jul-10 22:47 UTC
[Nouveau] [PATCH v2] PCI: Expose hidden NVIDIA HDA controllers
On Mon, Jul 08, 2019 at 01:17:44PM +0800, Daniel Drake wrote:> From: Lukas Wunner <lukas at wunner.de> > > The integrated HDA controller on Nvidia GPUs can be hidden with a bit in > the GPU's config space. Information about this scheme was provided by > NVIDIA on their forums. > > Many laptops now ship with this device hidden, meaning that Linux users > of affected platforms (where the HDMI connector comes off the NVIDIA GPU) > cannot use HDMI audio functionality. > > Some platforms have ACPI DSDT code that will make the device visible if > the HDMI cable was connected at boot time, but this does not handle the > hotplug case, and this limitation has also been confirmed under Windows. > > Avoid this issue by exposing the HDMI audio device on device enumeration > and resume. > > The GPU and HDA controller are two functions of the same PCI device > (VGA class device on function 0 and audio device on function 1). > The multifunction flag in the GPU's Header Type register is cleared when > the HDA controller is hidden and set if it's exposed, so reread the flag > after exposing the HDA. > > According to Ilia Mirkin, the HDA controller is only present on GPUs with > PCI ID values from MCP89's onwards, so do not touch config space on older > GPUs. > > 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. > > It's sensible to avoid exposing the HDA controller on dGPU setups, > especially because we've seen cases where the PCI BARs are not set > up correctly by the platform in this case, causing Linux to log > errors if the device is visible. This assumption of device class > accurately corresponding to product configuration is true for 6 of 6 > laptops recently checked at the Endless lab, and there are also signs of > agreement checking the data from 74 previously tested products, however > Ilia Mirkin comments that he's seen cases where it is not true. Anyway, it > looks like this quirk should fix audio support for the majority of > affected users. > > This commit takes inspiration from an earlier patch by Daniel Drake. > > Link: https://devtalk.nvidia.com/default/topic/1024022 > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75985 > 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> > Signed-off-by: Lukas Wunner <lukas at wunner.de> > Signed-off-by: Daniel Drake <drake at endlessm.com>I applied this (slightly revised as below) to pci/misc and I think we can still squeeze it in for v5.3. My revisions: - Don't write the enable bit if it's already set. - Log a note when enabling the HDA. I don't like writing undocumented config bits in *every* current and future NVIDIA GPU, so the note is just a hint that we're doing something slightly risky. - Use "hdr_type & 0x80" to match the other places we set pdev->multifunction. - Remove the commit log parts that don't seem relevant for future maintenance and add the URL to the original posting. Let me know if I broke anything. commit b678f90a1a6f Author: Lukas Wunner <lukas at wunner.de> Date: Mon Jul 8 13:17:44 2019 +0800 PCI: Enable NVIDIA HDA controllers 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 at 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> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index c66c0ca446c4..208aacf39329 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -5011,6 +5011,36 @@ DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_CLASS_SERIAL_UNKNOWN, 8, quirk_gpu_usb_typec_ucsi); +/* + * 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); +} +DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, + PCI_BASE_CLASS_DISPLAY, 16, quirk_nvidia_hda); +DECLARE_PCI_FIXUP_CLASS_RESUME_EARLY(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, + PCI_BASE_CLASS_DISPLAY, 16, quirk_nvidia_hda); + /* * Some IDT switches incorrectly flag an ACS Source Validation error on * completions for config read requests even though PCIe r4.0, sec diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h index 70e86148cb1e..66898463b81f 100644 --- a/include/linux/pci_ids.h +++ b/include/linux/pci_ids.h @@ -1336,6 +1336,7 @@ #define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS 0x0752 #define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP77_IDE 0x0759 #define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP73_SMBUS 0x07D8 +#define PCI_DEVICE_ID_NVIDIA_GEFORCE_320M 0x08A0 #define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS 0x0AA2 #define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP89_SATA 0x0D85
Daniel Drake
2019-Jul-11 05:36 UTC
[Nouveau] [PATCH v2] PCI: Expose hidden NVIDIA HDA controllers
On Thu, Jul 11, 2019 at 6:47 AM Bjorn Helgaas <helgaas at kernel.org> wrote:> I applied this (slightly revised as below) to pci/misc and I think we > can still squeeze it in for v5.3.Thanks. Tested briefly and it seems to be working fine!