Also, I realized after sending this that I should clarify something so there
isn't any confusion.
A bunch of people on the bug that was mentioned in b516ea586d71 ("PCI: Enable
NVIDIA HDA controllers") said that this worked perfectly for their P50
laptops. While I don't doubt that at all, it should be noted that the P50
quirk there is only present on a _very specific_ subset of P50 SKUs, so it's
quite likely that the people in that bug report just didn't have a P50 that
hits this issue. The relevant model numbers of the P50 with the flakey bioses
that require this quirk should be mentioned here:
https://bugzilla.kernel.org/show_bug.cgi?id=203003
On Wed, 2019-07-31 at 16:19 -0400, Lyude Paul wrote:
> This reverts commit b516ea586d717472178e6ef1c152e85608b0ce32.
>
> While this fixes audio for a number of users, this commit has the
> sideaffect of breaking the BIOS workaround that's required to make the
> GPU on the nvidia P50 work, by causing the GPU's PCI device function to
> stop working after it's been set to multifunction mode.
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> Fixes: b516ea586d71 ("PCI: Enable NVIDIA HDA controllers")
> Cc: Lukas Wunner <lukas@xxxxxxxxx>
> Cc: Daniel Drake <drake@xxxxxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Aaron Plattner <aplattner@xxxxxxxxxx>
> Cc: Peter Wu <peter@xxxxxxxxxxxxx>
> Cc: Ilia Mirkin <imirkin@xxxxxxxxxxxx>
> Cc: Karol Herbst <kherbst@xxxxxxxxxx>
> Cc: Maik Freudenberg <hhfeuer@xxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx
> ---
>
> I'm not really holding my breath on this patch to being accepted:
> there's a good chance there's a better solution for this (and I'm going
> to continue investigating for one after sending this patch), this is
> more just to start a conversation on what the proper way to fix this is.
>
> So, I'm kind of confused about why exactly this was implemented as an
> early boot quirk in the first place. If we're seeing the GPU's PCI
> device, we already know the GPU is there. Shouldn't we be able to check
> for the existence of the HDA device once we probe the GPU in nouveau?
> This would make a lot more sense and be a lot less troublesome. I can
> see that in the discussion on
>
> https://bugs.freedesktop.org/show_bug.cgi?id=75985
>
> That people mentioned that unloading nouveau then trying to reprobe for
> the audio device didn't work, but that still doesn't explain why this
> was implemented as an early quirk and not as something we just do before
> nouveau is setup. Can we maybe move this somewhere a little more
> sensible?
>
> drivers/pci/quirks.c | 30 ------------------------------
> include/linux/pci_ids.h | 1 -
> 2 files changed, 31 deletions(-)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 208aacf39329..c66c0ca446c4 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5011,36 +5011,6 @@ 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 c842735a4f45..f496fb619287 100644
> --- a/include/linux/pci_ids.h
> +++ b/include/linux/pci_ids.h
> @@ -1336,7 +1336,6 @@
> #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
>
--
Cheers,
Lyude Paul
