Re: [PATCH RFC] power: sequencing: pcie-m2: stop requiring subsystem IDs for WCN6855/WCN7850

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [High] pwrseq: pcie-m2: bare PCI_DEVICE() creates bogus serdev on
  USB-BT cards
--

commit 651d16502b81077112cba212f5fb84dc03306321
Author: Jens Glathe <jens.glathe@oldschoolsolutions.biz>

power: sequencing: pcie-m2: stop requiring subsystem IDs for WCN6855/WCN7850

This commit replaces the subsystem-specific PCI_DEVICE_SUB() entries for
Qualcomm WCN6855 (0x1103) and WCN7850 (0x1107) in pwrseq_m2_pci_ids[] with
bare PCI_DEVICE() entries.

> diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
> index 56c5d51293c10..72c721149dfae 100644
> --- a/drivers/power/sequencing/pwrseq-pcie-m2.c
> +++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
> @@ -217,15 +217,9 @@ static const struct pci_device_id pwrseq_m2_pci_ids[] = {
>  	  .driver_data = (kernel_ulong_t)"nxp,88w8987-bt" },
>  	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_QCOM, 0x1103, PCI_VENDOR_ID_QCOM, 0x0108),
>  	  .driver_data = (kernel_ulong_t)"qcom,qca2066-bt" },
> -	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_QCOM, 0x1103, PCI_VENDOR_ID_FOXCONN, 0xe105),
> +	{ PCI_DEVICE(PCI_VENDOR_ID_QCOM, 0x1103),
>  	  .driver_data = (kernel_ulong_t)"qcom,wcn6855-bt" },
> -	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_QCOM, 0x1103, PCI_VENDOR_ID_QCOM, 0x337e),
> -	  .driver_data = (kernel_ulong_t)"qcom,wcn6855-bt" },
> -	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_QCOM, 0x1107, PCI_VENDOR_ID_QCOM, 0x337c),
> -	  .driver_data = (kernel_ulong_t)"qcom,wcn7850-bt" },
> -	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_QCOM, 0x1107, PCI_VENDOR_ID_LENOVO, 0xe0e9),
> -	  .driver_data = (kernel_ulong_t)"qcom,wcn7850-bt" },
> -	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_QCOM, 0x1107, PCI_VENDOR_ID_FOXCONN, 0xe0ee),
> +	{ PCI_DEVICE(PCI_VENDOR_ID_QCOM, 0x1107),
>  	  .driver_data = (kernel_ulong_t)"qcom,wcn7850-bt" },
>  	{ } /* Sentinel */
>  };

[Severity: High]
Won't matching bare 0x1103 and 0x1107 device IDs reintroduce the regression
fixed by a39ac4651e3b ("power: sequencing: pcie-m2: Match WCN6855 and
WCN7851 UART BT variants by subdevice ID") whenever a USB-BT M.2 card is
plugged into a socketed M.2 Key E slot?

The pcie-m2-e-connector node describes the physical M.2 slot wiring on the
host board, not the card installed in it.  Boards with a general-purpose M.2
Key E socket (such as arch/arm64/boot/dts/qcom/hamoa-iot-evk.dts) wire the
SoC UART to the slot and define port@3 unconditionally in their static DT.

When a USB-BT WCN6855 or WCN7850/WCN7851 card is inserted into such a slot,
pwrseq_pcie_m2_create_serdev() -> pwrseq_pcie_m2_create_serdev_one() sees
port@3 on ctx->dev and matches 0x1103 or 0x1107 in pwrseq_m2_pci_ids[].  It
then creates a bogus bluetooth OF node and UART serdev device, causing
hci_qca to bind alongside btusb and fail with -ETIMEDOUT in qca_setup() on
the unconnected UART lines.

Also, the commit message notes that Lenovo T14s Gen 6 (17aa:e0e9) is missing
from the table, but 58a003302481 ("power: sequencing: pcie-m2: Add Lenovo
ThinkPad T14s gen6 WCN7850 subsystem PCI ids") already added that entry
above.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261106-pwrseq-bt-subsystem-v1-1-11fb09f63c93@oldschoolsolutions.biz?part=1