Re: [RESEND] USB PD broken on Lenovo P15gen2

[Heikki Krogerus]

Hi Nikolay,

Thanks for the report.

On Wed, Aug 30, 2023 at 04:07:55PM +0300, Nikolay Borisov wrote:
> 
> 
> 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;)

This part should be fixed.

> 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().

That "pd" member in struct typec_capability is optional. It can be
used if the driver has a set of USB PD capabilities meant for USB
Type-C port ready before the port is registered, but in UCSI driver
the PD stuff are registered after the port.

So I'm not sure there is anything wrong here.

> 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 ?

It looks like nobody ever checked is the command supported or not
before using it. That's a bug.

thanks,

-- 
heikki