Re: [PATCH] usb: typec: ucsi: acpi: Assume UCSI 1.0 on HP ZBook 8 G2i 14

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Mon, Oct 26, 2026 at 01:47:52AM +0200, Ihor Urazov via B4 Relay wrote:
> From: Ihor Urazov <z0rc3r@gmail.com>
> 
> The HP ZBook 8 G2i 14 (board 8ED9) exposes a working UCSI ACPI PPM, but
> its UCSI VERSION field reads zero until the first command completes.
> ucsi_register() rejects a zero version with -ENODEV, so no Type-C ports
> are registered.
> 
> The firmware's _DSM READ function (2) is a stub. The mailbox VERSION
> field is written only by the EC response handler, after a command
> completes, after which it reads 0x0100 (UCSI 1.0). The mailbox is
> 48 bytes with 16-byte MESSAGE_IN/MESSAGE_OUT fields, the UCSI 1.x
> layout, and _DSM function 5 is not implemented.
> 
> Add a DMI-specific read_version for this board that substitutes the
> version the firmware itself reports, UCSI 1.0, only when VERSION reads
> zero. A non-zero firmware version is used as is.
> 
> The same firmware defect on the HP ZBook Fury G1i 16 was discussed in
> "[RFC PATCH] usb: typec: ucsi: acpi: bootstrap PPM on HP systems with
> empty _DSM func 2" [1]. The defect was reported to HP as case
> 5166176673.
> 
> Tested on an HP ZBook 8 G2i 14 with BIOS Y70 01.02.08, from a fresh
> boot where VERSION reads zero: three connectors register, the PD
> contract and alternate modes of a Thunderbolt dock are reported, and
> its DisplayPort output stays up across the PPM reset in ucsi_init().
> Dock unplug/replug and s2idle suspend/resume update the connector
> state without errors.
> 
> Link: https://lore.kernel.org/linux-usb/f3M_fpjtt8FxDqGKcA84vqXmRbKzCBfpCrIK4-jCWvIscER51zkD8qD8FYpz75qZw51rMDRSkUyYlrBvLvdM8CGRY2l8TFVvr4MC1LdTzbc=@interstellar.eu/ [1]
> Fixes: c1b0bc2dabfa ("usb: typec: Add support for UCSI interface")
> Cc: stable@vger.kernel.org
> Cc: Francesco Orro <ncesco@interstellar.eu>
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Ihor Urazov <z0rc3r@gmail.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> Hi Heikki,
> 
> on the Fury G1i RFC you asked for the actual UCSI version instead of a
> guess. On this board the firmware itself reports 0x0100 once the first
> command completes (read back from the mailbox), and the mailbox layout and
> missing _DSM function 5 rule out 2.x. HP has been asked to report it from
> boot, case 5166176673.
> ---
>  drivers/usb/typec/ucsi/ucsi_acpi.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
> index 5697ccc24ec3..2421a92ecb0e 100644
> --- a/drivers/usb/typec/ucsi/ucsi_acpi.c
> +++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
> @@ -148,6 +148,34 @@ static const struct ucsi_operations ucsi_acer_ops = {
>  	.async_control = ucsi_acpi_async_control
>  };
>  
> +static int ucsi_hp_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;
> +
> +	/* Firmware fills in VERSION (1.0) only after the first command completes */
> +	if (!*version) {
> +		dev_warn(ua->dev, "UCSI version is zero, assuming 1.0\n");
> +		*version = UCSI_VERSION_1_0;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct ucsi_operations ucsi_hp_ops = {
> +	.read_version = ucsi_hp_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)
> @@ -196,6 +224,13 @@ static const struct dmi_system_id ucsi_acpi_quirks[] = {
>  		},
>  		.driver_data = (void *)&ucsi_acer_ops,
>  	},
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
> +			DMI_MATCH(DMI_BOARD_NAME, "8ED9"),
> +		},
> +		.driver_data = (void *)&ucsi_hp_ops,
> +	},
>  	{
>  		.matches = {
>  			DMI_MATCH(DMI_SYS_VENDOR, "LG Electronics"),
> 
> ---
> base-commit: 21a7f44fd0765fcc5194130b28767786eba1d1e7
> change-id: 20261026-ucsi-hp-zbook-8-g2i-4446ab6e5ed4
> 
> Best regards,
> --  
> Ihor Urazov <z0rc3r@gmail.com>
> 

-- 
heikki