Re: [PATCH 2/2] usb: typec: ucsi: Don't create power supplies for dGPUs

Greg KH
2023-05-17T18:59:00Z

On Wed, May 17, 2023 at 08:14:13PM +0300, Andy Shevchenko wrote:
> On Tue, May 16, 2023 at 01:25:41PM -0500, Mario Limonciello wrote:
> > power_supply_is_system_supplied() checks whether any power
> > supplies are present that aren't batteries to decide whether
> > the system is running on DC or AC. Downstream drivers use
> > this to make performance decisions.
> >
> > Navi dGPUs include an UCSI function that has been exported
> > since commit 17631e8ca2d3 ("i2c: designware: Add driver
> > support for AMD NAVI GPU").
> >
> > This UCSI function registers a power supply since commit
> > 992a60ed0d5e ("usb: typec: ucsi: register with power_supply class")
> > but this is not a system power supply.
> >
> > As the power supply for a dGPU is only for powering devices connected
> > to dGPU, create a device property to indicate that the UCSI endpoint
> > is only for the scope of `POWER_SUPPLY_SCOPE_DEVICE`.
>
> ...
>
> > +static const struct property_entry dgpu_properties[] = {
> > + /* USB-C doesn't power the system */
> > + PROPERTY_ENTRY_U8("scope", POWER_SUPPLY_SCOPE_DEVICE),
> > + {},
>
> Comma is not needed in terminator entry.

But it's encouraged!