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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZGULZU01tdqm1Xoc@smile.fi.intel.com>
Date:   Wed, 17 May 2023 20:14:13 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Mario Limonciello <mario.limonciello@....com>
Cc:     heikki.krogerus@...ux.intel.com, rafael@...nel.org,
        ajayg@...dia.com, linux-i2c@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org, Evan.Quan@....com, Lijo.Lazar@....com,
        Sanket.Goswami@....com
Subject: Re: [PATCH 2/2] usb: typec: ucsi: Don't create power supplies for
 dGPUs

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.

> +};

-- 
With Best Regards,
Andy Shevchenko