Re: [PATCH] usb: typec: ucsi: acpi: Assume UCSI 1.2 on Acer Nitro ANV15-41

[Heikki Krogerus]

On Thu, Sep 10, 2026 at 09:33:37AM +0700, Pannarat Wiriyaarritham wrote:
> The Acer Nitro ANV15-41 exposes a functional UCSI ACPI PPM but
> reports a UCSI VERSION value of zero.
> 
> ucsi_register() rejects a zero version with -ENODEV, leaving the
> system without registered USB Type-C connectors.
> 
> The PPM works correctly when using the UCSI 1.2 layout. With UCSI
> 1.2 assumed, both Type-C connectors register correctly and USB Power
> Delivery negotiation works.
> 
> Add a DMI-specific UCSI operation for the Acer Nitro ANV15-41 that
> substitutes UCSI 1.2 only when firmware reports a zero version.
> Preserve any valid non-zero firmware version.
> 
> Tested on an Acer Nitro ANV15-41 with BIOS V1.51.
> 
> Fixes: c1b0bc2dabfa ("usb: typec: Add support for UCSI interface")
> Cc: stable@xxxxxxxxxxxxxxx
> Assisted-by: LLM
> Signed-off-by: Pannarat Wiriyaarritham <pannarat.wiriyaarritham@xxxxxxxxxxxxxx>

Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
>  drivers/usb/typec/ucsi/ucsi_acpi.c | 34 ++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
> index 18286d3e9..5697ccc24 100644
> --- a/drivers/usb/typec/ucsi/ucsi_acpi.c
> +++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
> @@ -121,6 +121,33 @@ static const struct ucsi_operations ucsi_acpi_ops = {
>  	.async_control = ucsi_acpi_async_control
>  };
>  
> +static int ucsi_acer_read_version(struct ucsi *ucsi, u16 *version)
> +{
> +	struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
> +	int ret;
> +
> +	ret = ucsi_acpi_read_version(ucsi, version);
> +	if (ret)
> +		return ret;
> +
> +	if (!*version) {
> +		dev_warn(ua->dev, "UCSI version is zero, assuming 1.2\n");
> +		*version = UCSI_VERSION_1_2;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct ucsi_operations ucsi_acer_ops = {
> +	.read_version = ucsi_acer_read_version,
> +	.read_cci = ucsi_acpi_read_cci,
> +	.poll_cci = ucsi_acpi_poll_cci,
> +	.read_message_in = ucsi_acpi_read_message_in,
> +	.write_message_out = ucsi_acpi_write_message_out,
> +	.sync_control = ucsi_sync_control_common,
> +	.async_control = ucsi_acpi_async_control
> +};
> +
>  static int ucsi_gram_sync_control(struct ucsi *ucsi, u64 command, u32 *cci,
>  				  void *val, size_t len, void *msg_out,
>  				  size_t msg_out_size)
> @@ -162,6 +189,13 @@ static const struct ucsi_operations ucsi_gram_ops = {
>  };
>  
>  static const struct dmi_system_id ucsi_acpi_quirks[] = {
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "Nitro ANV15-41"),
> +		},
> +		.driver_data = (void *)&ucsi_acer_ops,
> +	},
>  	{
>  		.matches = {
>  			DMI_MATCH(DMI_SYS_VENDOR, "LG Electronics"),
> -- 
> 2.55.0

-- 
heikki