linux-kernel - Re: [RESEND] USB PD broken on Lenovo P15gen2

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Message-ID: <9841c4f5-614e-bfff-e725-2398fad4e927@suse.com>
Date:   Wed, 30 Aug 2023 16:07:55 +0300
From:   Nikolay Borisov <nik.borisov@...e.com>
To:     heikki.krogerus@...ux.intel.com,
        Greg KH <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Cc:     Anthony Iliopoulos <ailiopoulos@...e.com>
Subject: Re: [RESEND] USB PD broken on Lenovo P15gen2

On 28.08.23 г. 17:52 ч., Nikolay Borisov wrote:
> 
> [Resending as I had initially attached  a full acpi dump and it got 
> bounced from the usb mailing list]
> 
> Hello,
> 
> I'm not able to use usb PD on a Lenovo Thinkpad P15gen2 laptop. It's 
> equipped with 2 thunderbolt ports and a usb 3.2 gen2 usb port, all of 
> which are supposed to support PD 2.0:

<snip>
So I've been debugging this and what the PPM reports is the following:

modprobe-529501  [004] ..... 33507.058332: ucsi_register: Supported UCSI spec: 100
      kworker/4:0-524223  [004] ..... 33507.486591: ucsi_init_work: Connectors supported: 3
      kworker/4:0-524223  [004] ..... 33507.486592: ucsi_init_work: GET_CAP: USB_PD: 0 TYPEC_CURRENT: 1 POWER_VBUS: 0, POWER_OTHER: 0, POWER_AC_SUPPLY: 1, BATTERY_CHARGING: 0 bcVersion: 0x102 typec_version: 0x100 pd_version: 0x200 PDO_DETAILS: 0
      kworker/4:0-524223  [004] ..... 33507.682726: ucsi_init_work: [Register port 1]: OPMODE: E4 flag:1
      kworker/4:0-524223  [004] ..... 33508.850438: ucsi_init_work: [Register port 2]: OPMODE: E4 flag:1
      kworker/4:0-524223  [004] ..... 33509.986672: ucsi_init_work: [Register port 3]: OPMODE: E4 flag:1

So all three ports support DRP/USB2/USB3/ALT_MODE and they can be a provider.

I find it strange that USB_PD is reported as 0 yet pd_version is reported as 2. I contacted Lenovo's support and they confirmed that this particular model indeed supports PD 3.0 on all USBC ports.

I see a couple of problems with the current upstream code:

1. It assumes that USB_PD is valid because the PD version from pd_version is being propagated to several places (like in ucsi_register_port() cap->pd_revision = ucsi->cap.pd_version;)
2. When typec_register_port() is called from ucsi_register_port() cap->pd is 0 hence the port->pd = cap->pd; assignment in typec_register_port is a noop. In fact I don't see where cap->pd is being initialized since we initialize con->pd when we call usb_power_delivery_register in ucsi_register_port().

Is it mandatory that GET_PDOS is supported if PD is supported, the UCSI spec doesn't say anything other than GET_PDOS is optional and signaled by bit in the GET_CAP call ?