linux-kernel - Re: [PATCH 0/5] acpi: Store _PLD information and convert users

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Message-ID: <CACeCKaeYRWxS1kPX6TvQHvn_5H_u-+MKWmdh5XQeCdZ-Wj93Hw@mail.gmail.com>
Date:   Thu, 9 Dec 2021 11:45:27 -0800
From:   Prashant Malani <pmalani@...omium.org>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        linux-acpi@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/5] acpi: Store _PLD information and convert users

Hey Heikki,

On Thu, Dec 9, 2021 at 2:06 AM Heikki Krogerus
<heikki.krogerus@...ux.intel.com> wrote:
>
> Hi,
>
> Thanks for testing these..
>
> On Wed, Dec 08, 2021 at 07:45:26PM -0800, Prashant Malani wrote:
> > Hi Heikki,
> >
> > On Tue, Dec 7, 2021 at 6:37 AM Heikki Krogerus
> > <heikki.krogerus@...ux.intel.com> wrote:
> > >
> > > Hi,
> > >
> > > This removes the need for the drivers to always separately evaluate
> > > the _PLD. With the USB Type-C connector and USB port mapping this
> > > allows us to start using the component framework and remove the custom
> > > APIs.
> > >
> > > So far the only users of the _PLD information have been the USB
> > > drivers, but it seems it will be used also at least in some camera
> > > drivers later. These nevertheless touch mostly USB drivers.
> > >
> > > Rafael, is it still OK if Greg takes these?
> > >
> > > Prashant, can you test these?
> >
> > I've applied the patches to a system with the requisite _PLD entries
> > in firmware, and I'm not sure I can see the connectors getting created
> > correctly.
> >
> > My setup is:
> >
> > Chromebook ------> Dell WD19TB dock (in USB+DisplayPort Alternate
> > Mode) ----> USB Thumb drive.
> >
> > Here is the lsusb -t output before connecting the dock (omitting
> > unrelated busses):
> > localhost ~ # lsusb -t
> > /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/3p, 10000M/x2
> >
> > Here is the lsusb -t output (omitting unrelated busses):
> > localhost ~ # lsusb -t
> > /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/3p, 10000M/x2
> >     |__ Port 2: Dev 15, If 0, Class=Hub, Driver=hub/4p, 10000M
> >         |__ Port 3: Dev 16, If 0, Class=Hub, Driver=hub/4p, 5000M
> >             |__ Port 3: Dev 18, If 0, Class=Mass Storage,
> > Driver=usb-storage, 5000M
> >         |__ Port 4: Dev 17, If 0, Class=Vendor Specific Class,
> > Driver=r8152, 5000M
> >
> > I see the connector symlink for the root hub:
> >
> > localhost ~ # cd /sys/bus/usb/devices
> > localhost /sys/bus/usb/devices # ls 2-2/port/connector
> > data_role  device  firmware_node  port1-cable  port1-partner  power
> > power_operation_mode  power_role  preferred_role  subsystem
> > supported_accessory_modes  uevent  usb2-port2  usb3-port2
> > usb_power_delivery_revision  usb_typec_revision  vconn_source
> >
> > But for none of the children devices:
> >
> > localhost /sys/bus/usb/devices # ls 2-2.3/port/connector
> > ls: cannot access '2-2.3/port/connector': No such file or directory
> > localhost /sys/bus/usb/devices # ls 2-2.3.3/port/connector
> > ls: cannot access '2-2.3.3/port/connector': No such file or directory
> > localhost /sys/bus/usb/devices # ls 2-2.3\:1.0/port/connector
> > ls: cannot access '2-2.3:1.0/port/connector': No such file or directory
> > localhost /sys/bus/usb/devices # ls 2-2.3.3\:1.0/port/connector
> > ls: cannot access '2-2.3.3:1.0/port/connector': No such file or directory
> >
> > Is this as you intended with the series? My interpretation was that
> > each connected usb device would get a "connector" symlink, but I may
> > have misinterpreted this.
>
> It is as intended. The usb ports on the board will have the connector
> symlink, not the devices attached to them - the firmware is only aware
> of the connectors on the board of course. It looks like this series is
> working as it should.

Thanks for clarifying my understanding here.

>
> If you want to extend this solution so that also every device in the
> usb topology will have the link to the connector on board, then that
> should be now possible, but that is out side of the scope of this
> series. You need to propose that separately.
>
> But I must ask, why can't you just walk down the topology until you
> reach the on-board ports that will have the connector links?
>

Right, we can certainly do that; having it in each device is just
convenient. But as you said, that's the subject of another series.

You mentioned there would be a v2, so I'll add my Tested-By then.

Best regards,