Re: [PATCH] usb: typec: ucsi: acpi: Disable on devices with broken firmware

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, May 12, 2026 at 01:59:34AM +0800, Rong Zhang wrote:
> Some Lenovo devices have broken firmware, which reads/writes half-valid-
> half-garbage values.

How does this work with this firmware on other operating systems?  What
is the odds of fixing the firmware?

> Given that everything is broken, disable ucsi_acpi on these devices. The
> impact of disabling it is minimal, as Lenovo laptops usually have most
> USCI commands more or less stubbed, and the EC can always handles USB-C
> events on its own.
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=221065#c33
> Signed-off-by: Rong Zhang <i@rong.moe>
> ---
>  drivers/usb/typec/ucsi/ucsi_acpi.c | 91 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 91 insertions(+)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
> index 6b92f296e985..7632b441d401 100644
> --- a/drivers/usb/typec/ucsi/ucsi_acpi.c
> +++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
> @@ -155,6 +155,91 @@ static const struct dmi_system_id ucsi_acpi_quirks[] = {
>  	{ }
>  };
>  
> +static const struct dmi_system_id ucsi_acpi_broken_devices[] = {
> +	/* Firmware reads/writes half-valid-half-garbage values. */
> +
> +	/* BIOS: P1CN??WW */
> +	{
> +		.ident = "Lenovo IdeaPad 5 2-in-1 14AHP9",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83DR"),
> +		},
> +	},
> +	{
> +		.ident = "Lenovo IdeaPad 5 2-in-1 16AHP9",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83DS"),
> +		},
> +	},
> +
> +	/* BIOS: R0CN??WW */
> +	{
> +		.ident = "Lenovo IdeaPad Slim 5 14AKP10",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83NJ"),
> +		},
> +	},
> +	{
> +		.ident = "Lenovo IdeaPad Slim 5 14AKP10",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83HX"),
> +		},
> +	},
> +	{
> +		.ident = "Lenovo IdeaPad Slim 5 16AKP10",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83HY"),
> +		},
> +	},
> +
> +	/* BIOS: QXCN??WW */
> +	{
> +		.ident = "Lenovo Yoga 7 2-in-1 14AKP10",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83JR"),
> +		},
> +	},
> +	{
> +		.ident = "Lenovo Yoga 7 2-in-1 16AKP10",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83JU"),
> +		},
> +	},
> +
> +	/* BIOS: LNCN??WW */
> +	{
> +		.ident = "Lenovo Yoga Pro 7 14ARP8",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83AU"),
> +		},
> +	},
> +	{
> +		.ident = "Lenovo Slim Pro 7 14ARP8",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83AX"),
> +		},
> +	},
> +
> +	/* BIOS: PSCN??WW */
> +	{
> +		.ident = "Lenovo Yoga Pro 7 14ASP9",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "83HN"),
> +		},
> +	},
> +	{ }
> +};

That is a lot of devices to exclude, are you sure that none of them will
ever work properly?

thanks,

greg k-h