linux-kernel - Re: [PATCH v4 7/8] usb: typec: ucsi: Support mode selection to activate altmodes

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] [day] [month] [year] [list]

Message-ID: <CAMMMRMcpuaTpJ3=zO0SafaeRPxTkAEEQrS-mDRKFBTc3yESM6A@mail.gmail.com>
Date: Sat, 17 Jan 2026 20:34:54 +0100
From: Andrei Kuchynski <akuchynski@...omium.org>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>, Benson Leung <bleung@...omium.org>, 
	Jameson Thies <jthies@...gle.com>, linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org, 
	chrome-platform@...ts.linux.dev, Tzung-Bi Shih <tzungbi@...nel.org>, 
	Guenter Roeck <groeck@...omium.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>, 
	Łukasz Bartosik <ukaszb@...omium.org>, 
	Abel Vesa <abel.vesa@...aro.org>, Pooja Katiyar <pooja.katiyar@...el.com>, 
	Johan Hovold <johan@...nel.org>, Hsin-Te Yuan <yuanhsinte@...omium.org>, Madhu M <madhu.m@...el.com>, 
	Venkat Jayaraman <venkat.jayaraman@...el.com>
Subject: Re: [PATCH v4 7/8] usb: typec: ucsi: Support mode selection to
 activate altmodes

On Thu, Jan 15, 2026 at 3:59 PM Heikki Krogerus
<heikki.krogerus@...ux.intel.com> wrote:
>
> Tue, Jan 13, 2026 at 01:05:35PM +0000, Andrei Kuchynski kirjoitti:
> > If the ucsi port driver supports modes selection, it should implement
> > `add_partner_altmodes` and `remove_partner_altmodes` ucsi operations. With
> > these operations the driver can manage the mode selection process.
> > Once partner altmodes are registered, `add_partner_altmodes` is called to
> > start the mode selection. When the partner is unregistered,
> > `remove_partner_altmodes` is supposed to stop any ongoing processes and
> > clean up the resources.
> >
> > `typec_altmode_state_update` informes mode selection about the current mode
> > of the Type-C connector.
> >
> > Signed-off-by: Andrei Kuchynski <akuchynski@...omium.org>
> > ---
> >  drivers/usb/typec/ucsi/ucsi.c | 11 +++++++++++
> >  drivers/usb/typec/ucsi/ucsi.h |  4 ++++
> >  2 files changed, 15 insertions(+)
> >
> > diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> > index deb210c066cb5..4a6e23b55b10c 100644
> > --- a/drivers/usb/typec/ucsi/ucsi.c
> > +++ b/drivers/usb/typec/ucsi/ucsi.c
> > @@ -314,6 +314,7 @@ void ucsi_altmode_update_active(struct ucsi_connector *con)
> >  {
> >       const struct typec_altmode *altmode = NULL;
> >       u64 command;
> > +     u16 svid = 0;
> >       int ret;
> >       u8 cur;
> >       int i;
> > @@ -335,6 +336,10 @@ void ucsi_altmode_update_active(struct ucsi_connector *con)
> >       for (i = 0; con->partner_altmode[i]; i++)
> >               typec_altmode_update_active(con->partner_altmode[i],
> >                                           con->partner_altmode[i] == altmode);
> > +
> > +     if (altmode)
> > +             svid = altmode->svid;
> > +     typec_altmode_state_update(con->partner, svid, 0);
> >  }
> >
> >  static int ucsi_altmode_next_mode(struct typec_altmode **alt, u16 svid)
> > @@ -609,6 +614,8 @@ static int ucsi_register_altmodes(struct ucsi_connector *con, u8 recipient)
> >                       desc.vdo = alt[j].mid;
> >                       desc.svid = alt[j].svid;
> >                       desc.roles = TYPEC_PORT_DRD;
> > +                     desc.mode_selection = con->ucsi->ops->add_partner_altmodes &&
> > +                                     con->ucsi->cap.features & UCSI_CAP_ALT_MODE_OVERRIDE;
>
> Can't you just use that con->typec_cap.no_mode_control flag here?
>

Thanks. It looks much better.

> Maybe also consider squashing that patch 3/8 into this one while at it.
>

I agree. Patch 3/8 was part of a mode priority series. Now there's no
point in leaving a single line of code in a separate patch.

Thank you for your review of the series!
I will send the subsequent series with all the changes.

Andrei