linux-kernel - Re: [PATCH 8/8] platform/chrome: cros_ec_typec: Disable auto

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Message-ID: <CANFp7mVir-XEuVBd+kbQq0+5Si0CBo8TNxcdNpG6X+PDR-J1Zw@mail.gmail.com>
Date: Wed, 25 Sep 2024 10:39:00 -0700
From: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: heikki.krogerus@...ux.intel.com, tzungbi@...nel.org, jthies@...gle.com, 
	pmalani@...omium.org, akuchynski@...gle.com, 
	Benson Leung <bleung@...omium.org>, Guenter Roeck <groeck@...omium.org>, 
	chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 8/8] platform/chrome: cros_ec_typec: Disable auto_enter

On Wed, Sep 25, 2024 at 10:03 AM Dmitry Baryshkov
<dmitry.baryshkov@...aro.org> wrote:
>
> On Wed, Sep 25, 2024 at 09:25:09AM GMT, Abhishek Pandit-Subedi wrote:
> > Altmodes with cros_ec are either automatically entered by the EC or
> > entered by typecd in userspace so we should not auto enter from the
> > kernel.
>
> This makes policy decision for the whole platform. Consider somebody
> running normal Linux distro on chromebooks. Can this be configured by
> the userspace itself?

This is just the default for when the driver registers. You will then
find that there is now a sysfs entry for auto_enter that you can
control from userspace to allow you to auto-enter the mode on partner
attach (which you could probably write a udev rule for).

I still need to send a follow-up for how to handle auto-enter when
there are multiple modes available on the partner that are all
enabled. This first patch series is mostly about supporting existing
use-case for ChromeOS.


>
> >
> > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> > ---
> >
> >  drivers/platform/chrome/cros_ec_typec.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> > index ec13d84d11b8..e06a0f2712ce 100644
> > --- a/drivers/platform/chrome/cros_ec_typec.c
> > +++ b/drivers/platform/chrome/cros_ec_typec.c
> > @@ -294,6 +294,7 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
> >       desc.svid = USB_TYPEC_DP_SID;
> >       desc.mode = USB_TYPEC_DP_MODE;
> >       desc.vdo = DP_PORT_VDO;
> > +     desc.no_auto_enter = true;
> >       amode = cros_typec_register_displayport(port, &desc,
> >                                               typec->ap_driven_altmode);
> >       if (IS_ERR(amode))
> > @@ -314,6 +315,7 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
> >               memset(&desc, 0, sizeof(desc));
> >               desc.svid = USB_TYPEC_TBT_SID;
> >               desc.mode = TYPEC_ANY_MODE;
> > +             desc.no_auto_enter = true;
> >               amode = cros_typec_register_thunderbolt(port, &desc);
> >               if (IS_ERR(amode))
> >                       return PTR_ERR(amode);
> > --
> > 2.46.0.792.g87dc391469-goog
> >
>
> --
> With best wishes
> Dmitry