Re: [PATCH v2 2/2] usb: typec: ucsi: acpi: Assume UCSI 1.2 on Lenovo ThinkPad T14 Gen 2a

[sashiko-bot@kernel.org]

> From: Stanisław Titenko <kernel@resetko.pl>
> 
> The Lenovo ThinkPad T14 Gen 2a exposes a functional UCSI ACPI PPM but
> the firmware leaves the VERSION field of the UCSI mailbox at zero.
> 
> ucsi_register() rejects a zero version with -ENODEV, leaving the
> system without registered USB Type-C connectors. Without an OPM, the
> embedded controller does not complete DisplayPort Alternate Mode setup
> when a USB-C dock or monitor that supplies power is connected after
> boot, so the display stays dark while USB and charging work.
> 
> Use the zero version quirk for the ThinkPad T14 Gen 2a, matching the
> two board names of this model (20XK and 20XL).
> 
> Tested on a ThinkPad T14 Gen 2a (20XK) with BIOS 1.33 (R1MET63W):
> both Type-C connectors register, and plugging and replugging a USB-C
> monitor with an integrated hub and power delivery brings up
> DisplayPort Alternate Mode each time.
> 
> Reported-by: Daniel Dev <daniel.dev@noex.uk>
> Closes: https://lore.kernel.org/linux-usb/b1Wn_eFvTFShGbd970WWl4CWhge_6P2x7Wb6rab3QHNlE4OJ4p__O-QN3B6I-308ftr5oV5Zr7vywA0vdvmtNw6E0YJnVM2ek_5DcFnkXB0=@noex.uk/
> Fixes: c1b0bc2dabfa ("usb: typec: Add support for UCSI interface")
> Cc: stable@vger.kernel.org
> Assisted-by: pi:claude-opus-5-5
> Signed-off-by: Stanisław Titenko <kernel@resetko.pl>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261103-ucsi-lenovo-t14g2a-v2-0-e85c659b56a2@resetko.pl?part=2