linux-kernel - Re: [PATCH 3/8] usb: typec: ucsi: yoga-c630: remove duplicate AltModes

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Message-ID: <aFprFG2Pmnx1aAXT@kuha.fi.intel.com>
Date: Tue, 24 Jun 2025 12:08:36 +0300
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH 3/8] usb: typec: ucsi: yoga-c630: remove duplicate
 AltModes

On Sat, Jun 21, 2025 at 09:12:58PM +0300, Dmitry Baryshkov wrote:
> On Lenovo Yoga C630 the EC firmware is buggy and it returns duplicate
> AltModes over and over again instead of returning an empty one, as
> demanded by the spec. Ignore extra altmodes by zeroing them in the
> update_altmodes() callback. It is not possible to shortcut that in the
> sync_control() callback since we need to know if the AltMode matches the
> first reported AltMode or not.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
>  drivers/usb/typec/ucsi/ucsi_yoga_c630.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_yoga_c630.c b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
> index 47e8dd5b255b2b306dd9c3d6ac8c3b896954981a..7cc1342d6e2f1d2c6f5b95caa48a711a280b91d3 100644
> --- a/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
> +++ b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
> @@ -71,6 +71,28 @@ static int yoga_c630_ucsi_async_control(struct ucsi *ucsi, u64 command)
>  	return yoga_c630_ec_ucsi_write(uec->ec, (u8*)&command);
>  }
>  
> +static bool yoga_c630_ucsi_update_altmodes(struct ucsi *ucsi,
> +					   u8 recipient,
> +					   struct ucsi_altmode *orig,
> +					   struct ucsi_altmode *updated)
> +{
> +	int i;
> +
> +	if (orig[0].svid == 0 || recipient != UCSI_RECIPIENT_SOP)
> +		return false;
> +
> +	/* EC is nice and repeats altmodes again and again. Ignore copies. */
> +	for (i = 1; i < UCSI_MAX_ALTMODES; i++) {
> +		if (orig[i].svid == orig[0].svid) {
> +			dev_dbg(ucsi->dev, "Found duplicate altmodes, starting from %d\n", i);
> +			memset(&orig[i], 0, (UCSI_MAX_ALTMODES - i) * sizeof(*orig));
> +			break;
> +		}
> +	}
> +
> +	return false;
> +}
> +
>  static const struct ucsi_operations yoga_c630_ucsi_ops = {
>  	.read_version = yoga_c630_ucsi_read_version,
>  	.read_cci = yoga_c630_ucsi_read_cci,
> @@ -78,6 +100,7 @@ static const struct ucsi_operations yoga_c630_ucsi_ops = {
>  	.read_message_in = yoga_c630_ucsi_read_message_in,
>  	.sync_control = ucsi_sync_control_common,
>  	.async_control = yoga_c630_ucsi_async_control,
> +	.update_altmodes = yoga_c630_ucsi_update_altmodes,
>  };
>  
>  static int yoga_c630_ucsi_notify(struct notifier_block *nb,
> 
> -- 
> 2.39.5

-- 
heikki