Re: [RESEND] PCI: NVIDIA GeForce MX230 (10de:1d11) falls off the bus right after "Enabling HDA controller" quirk on Acer Aspire A515-53G

[Lukas Wunner <lukas@wunner.de>]

On Sun, Oct 11, 2026 at 10:03:11AM +0700, Krittikun Wongnin wrote:
> On an Acer Aspire A515-53G (Intel Whiskey Lake + NVIDIA GeForce MX230,
> Optimus), the discrete GPU becomes inaccessible within ~15 ms of being
> enumerated at boot, immediately after quirk_nvidia_hda() logs
> "Enabling HDA controller". From then on, config space reads return all
> ones and no driver can use the device.

That's unusual, I don't recall seeing any other report about
such behavior.

> - I have not yet built a kernel with quirk_nvidia_hda() disabled to
>   prove the quirk is the trigger. I plan to do this and will report
>   the result. The 4.15 test differs from 7.1 in many ways besides the
>   quirk.

Below is a small debug patch to avoid the write to 0x488 and also
print the current value of the register to dmesg.  Does it help?

> If the quirk is the cause, would a DMI- or subsystem-ID-based exclusion
> (Acer 1025:130f), or skipping the quirk for class 0x0302 devices that
> report no HDA codec, be acceptable? I am happy to test patches and
> provide full dmesg, lspci -vvv (as root), and acpidump output.

Yes, output of "lspci -vvvxxxx" would be appreciated.

Let's first try to find the root cause before thinking about possible
solutions.

Thanks,

Lukas

-- >8 --

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index de9bbcc..51d3b65 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5863,8 +5863,8 @@ static void quirk_nvidia_hda(struct pci_dev *gpu)
 	if (val & BIT(25))
 		return;
 
-	pci_info(gpu, "Enabling HDA controller\n");
-	pci_write_config_dword(gpu, 0x488, val | BIT(25));
+	pci_info(gpu, "Enabling HDA controller %#x -> %#x\n", val, val | BIT(25));
+	// 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);