RE: [PATCH 4.16 REGRESSION fix] Revert "typec: tcpm: Only request matching pdos"

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On 06 March 2018 09:50, Hans de Goede wrote:

> Commit 57e6f0d7b804 ("typec: tcpm: Only request matching pdos") is causing
> a regression, before this commit e.g. the GPD win and GPD pocket devices
> were charging at 9V 3A with a PD charger, now they are instead slowly
> discharging  at 5V 0.4A, as this commit causes the ports max_snk_mv/ma/mw
> settings to be completely ignored.
> 
> Arguably the way to fix this would be to add a PDO_VAR() describing the
> voltage range to the snk_caps of boards which can handle any voltage in
> their range, but the "typec: tcpm: Only request matching pdos" commit
> looks at the type of PDO advertised by the source/charger and if that
> is fixed (as it typically is) only compairs against PDO_FIXED entries
> in the snk_caps so supporting a range of voltage would require adding a
> PDO_FIXED entry for *every possible* voltage to snk_caps.
> 
> AFAICT there is no reason why a fixed source_cap cannot be matched against
> a variable snk_cap, so at a minimum the commit should be rewritten to
> support that.
> 
> For now lets revert the "typec: tcpm: Only request matching pdos" commit,
> fixing the regression.
> 
> Cc: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>

Thanks Hans. Sadly I alluded to this problem before the patch was pulled in but
this was seemingly missed:

 https://lkml.org/lkml/2017/11/28/186

FWIW, Acked-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>

> ---
>  drivers/usb/typec/tcpm.c | 163 ++++++++++++-----------------------------------
>  1 file changed, 42 insertions(+), 121 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> index bfcaf6618a1f..735a6dd74c20 100644
> --- a/drivers/usb/typec/tcpm.c
> +++ b/drivers/usb/typec/tcpm.c
> @@ -254,9 +254,6 @@ struct tcpm_port {
>  	unsigned int nr_src_pdo;
>  	u32 snk_pdo[PDO_MAX_OBJECTS];
>  	unsigned int nr_snk_pdo;
> -	unsigned int nr_fixed; /* number of fixed sink PDOs */
> -	unsigned int nr_var; /* number of variable sink PDOs */
> -	unsigned int nr_batt; /* number of battery sink PDOs */
>  	u32 snk_vdo[VDO_MAX_OBJECTS];
>  	unsigned int nr_snk_vdo;
> 
> @@ -1786,90 +1783,39 @@ static int tcpm_pd_check_request(struct tcpm_port
> *port)
>  	return 0;
>  }
> 
> -#define min_power(x, y) min(pdo_max_power(x), pdo_max_power(y))
> -#define min_current(x, y) min(pdo_max_current(x), pdo_max_current(y))
> -
> -static int tcpm_pd_select_pdo(struct tcpm_port *port, int *sink_pdo,
> -			      int *src_pdo)
> +static int tcpm_pd_select_pdo(struct tcpm_port *port)
>  {
> -	unsigned int i, j, max_mw = 0, max_mv = 0, mw = 0, mv = 0, ma = 0;
> +	unsigned int i, max_mw = 0, max_mv = 0;
>  	int ret = -EINVAL;
> 
>  	/*
> -	 * Select the source PDO providing the most power which has a
> -	 * matchig sink cap.
> +	 * Select the source PDO providing the most power while staying within
> +	 * the board's voltage limits. Prefer PDO providing exp
>  	 */
>  	for (i = 0; i < port->nr_source_caps; i++) {
>  		u32 pdo = port->source_caps[i];
>  		enum pd_pdo_type type = pdo_type(pdo);
> +		unsigned int mv, ma, mw;
> 
> -		if (type == PDO_TYPE_FIXED) {
> -			for (j = 0; j < port->nr_fixed; j++) {
> -				if (pdo_fixed_voltage(pdo) ==
> -				    pdo_fixed_voltage(port->snk_pdo[j])) {
> -					ma = min_current(pdo, port->snk_pdo[j]);
> -					mv = pdo_fixed_voltage(pdo);
> -					mw = ma * mv / 1000;
> -					if (mw > max_mw ||
> -					    (mw == max_mw && mv > max_mv)) {
> -						ret = 0;
> -						*src_pdo = i;
> -						*sink_pdo = j;
> -						max_mw = mw;
> -						max_mv = mv;
> -					}
> -					/* There could only be one fixed pdo
> -					 * at a specific voltage level.
> -					 * So breaking here.
> -					 */
> -					break;
> -				}
> -			}
> -		} else if (type == PDO_TYPE_BATT) {
> -			for (j = port->nr_fixed;
> -			     j < port->nr_fixed +
> -				 port->nr_batt;
> -			     j++) {
> -				if (pdo_min_voltage(pdo) >=
> -				     pdo_min_voltage(port->snk_pdo[j]) &&
> -				     pdo_max_voltage(pdo) <=
> -				     pdo_max_voltage(port->snk_pdo[j])) {
> -					mw = min_power(pdo, port->snk_pdo[j]);
> -					mv = pdo_min_voltage(pdo);
> -					if (mw > max_mw ||
> -					    (mw == max_mw && mv > max_mv)) {
> -						ret = 0;
> -						*src_pdo = i;
> -						*sink_pdo = j;
> -						max_mw = mw;
> -						max_mv = mv;
> -					}
> -				}
> -			}
> -		} else if (type == PDO_TYPE_VAR) {
> -			for (j = port->nr_fixed +
> -				 port->nr_batt;
> -			     j < port->nr_fixed +
> -				 port->nr_batt +
> -				 port->nr_var;
> -			     j++) {
> -				if (pdo_min_voltage(pdo) >=
> -				     pdo_min_voltage(port->snk_pdo[j]) &&
> -				     pdo_max_voltage(pdo) <=
> -				     pdo_max_voltage(port->snk_pdo[j])) {
> -					ma = min_current(pdo, port->snk_pdo[j]);
> -					mv = pdo_min_voltage(pdo);
> -					mw = ma * mv / 1000;
> -					if (mw > max_mw ||
> -					    (mw == max_mw && mv > max_mv)) {
> -						ret = 0;
> -						*src_pdo = i;
> -						*sink_pdo = j;
> -						max_mw = mw;
> -						max_mv = mv;
> -					}
> -				}
> -			}
> +		if (type == PDO_TYPE_FIXED)
> +			mv = pdo_fixed_voltage(pdo);
> +		else
> +			mv = pdo_min_voltage(pdo);
> +
> +		if (type == PDO_TYPE_BATT) {
> +			mw = pdo_max_power(pdo);
> +		} else {
> +			ma = min(pdo_max_current(pdo),
> +				 port->max_snk_ma);
> +			mw = ma * mv / 1000;
> +		}
> +
> +		/* Perfer higher voltages if available */
> +		if ((mw > max_mw || (mw == max_mw && mv > max_mv)) &&
> +		    mv <= port->max_snk_mv) {
> +			ret = i;
> +			max_mw = mw;
> +			max_mv = mv;
>  		}
>  	}
> 
> @@ -1881,14 +1827,13 @@ static int tcpm_pd_build_request(struct tcpm_port
> *port, u32 *rdo)
>  	unsigned int mv, ma, mw, flags;
>  	unsigned int max_ma, max_mw;
>  	enum pd_pdo_type type;
> -	int src_pdo_index, snk_pdo_index;
> -	u32 pdo, matching_snk_pdo;
> +	int index;
> +	u32 pdo;
> 
> -	if (tcpm_pd_select_pdo(port, &snk_pdo_index, &src_pdo_index) < 0)
> +	index = tcpm_pd_select_pdo(port);
> +	if (index < 0)
>  		return -EINVAL;
> -
> -	pdo = port->source_caps[src_pdo_index];
> -	matching_snk_pdo = port->snk_pdo[snk_pdo_index];
> +	pdo = port->source_caps[index];
>  	type = pdo_type(pdo);
> 
>  	if (type == PDO_TYPE_FIXED)
> @@ -1896,28 +1841,26 @@ static int tcpm_pd_build_request(struct tcpm_port
> *port, u32 *rdo)
>  	else
>  		mv = pdo_min_voltage(pdo);
> 
> -	/* Select maximum available current within the sink pdo's limit */
> +	/* Select maximum available current within the board's power limit */
>  	if (type == PDO_TYPE_BATT) {
> -		mw = min_power(pdo, matching_snk_pdo);
> -		ma = 1000 * mw / mv;
> +		mw = pdo_max_power(pdo);
> +		ma = 1000 * min(mw, port->max_snk_mw) / mv;
>  	} else {
> -		ma = min_current(pdo, matching_snk_pdo);
> -		mw = ma * mv / 1000;
> +		ma = min(pdo_max_current(pdo),
> +			 1000 * port->max_snk_mw / mv);
>  	}
> +	ma = min(ma, port->max_snk_ma);
> 
>  	flags = RDO_USB_COMM | RDO_NO_SUSPEND;
> 
>  	/* Set mismatch bit if offered power is less than operating power */
> +	mw = ma * mv / 1000;
>  	max_ma = ma;
>  	max_mw = mw;
>  	if (mw < port->operating_snk_mw) {
>  		flags |= RDO_CAP_MISMATCH;
> -		if (type == PDO_TYPE_BATT &&
> -		    (pdo_max_power(matching_snk_pdo) > pdo_max_power(pdo)))
> -			max_mw = pdo_max_power(matching_snk_pdo);
> -		else if (pdo_max_current(matching_snk_pdo) >
> -			 pdo_max_current(pdo))
> -			max_ma = pdo_max_current(matching_snk_pdo);
> +		max_mw = port->operating_snk_mw;
> +		max_ma = max_mw * 1000 / mv;
>  	}
> 
>  	tcpm_log(port, "cc=%d cc1=%d cc2=%d vbus=%d vconn=%s polarity=%d",
> @@ -1926,16 +1869,16 @@ static int tcpm_pd_build_request(struct tcpm_port
> *port, u32 *rdo)
>  		 port->polarity);
> 
>  	if (type == PDO_TYPE_BATT) {
> -		*rdo = RDO_BATT(src_pdo_index + 1, mw, max_mw, flags);
> +		*rdo = RDO_BATT(index + 1, mw, max_mw, flags);
> 
>  		tcpm_log(port, "Requesting PDO %d: %u mV, %u mW%s",
> -			 src_pdo_index, mv, mw,
> +			 index, mv, mw,
>  			 flags & RDO_CAP_MISMATCH ? " [mismatch]" : "");
>  	} else {
> -		*rdo = RDO_FIXED(src_pdo_index + 1, ma, max_ma, flags);
> +		*rdo = RDO_FIXED(index + 1, ma, max_ma, flags);
> 
>  		tcpm_log(port, "Requesting PDO %d: %u mV, %u mA%s",
> -			 src_pdo_index, mv, ma,
> +			 index, mv, ma,
>  			 flags & RDO_CAP_MISMATCH ? " [mismatch]" : "");
>  	}
> 
> @@ -3667,19 +3610,6 @@ int tcpm_update_sink_capabilities(struct tcpm_port
> *port, const u32 *pdo,
>  }
>  EXPORT_SYMBOL_GPL(tcpm_update_sink_capabilities);
> 
> -static int nr_type_pdos(const u32 *pdo, unsigned int nr_pdo,
> -			enum pd_pdo_type type)
> -{
> -	int count = 0;
> -	int i;
> -
> -	for (i = 0; i < nr_pdo; i++) {
> -		if (pdo_type(pdo[i]) == type)
> -			count++;
> -	}
> -	return count;
> -}
> -
>  struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
>  {
>  	struct tcpm_port *port;
> @@ -3725,15 +3655,6 @@ struct tcpm_port *tcpm_register_port(struct device
> *dev, struct tcpc_dev *tcpc)
>  					  tcpc->config->nr_src_pdo);
>  	port->nr_snk_pdo = tcpm_copy_pdos(port->snk_pdo, tcpc->config-
> >snk_pdo,
>  					  tcpc->config->nr_snk_pdo);
> -	port->nr_fixed =  nr_type_pdos(port->snk_pdo,
> -				       port->nr_snk_pdo,
> -				       PDO_TYPE_FIXED);
> -	port->nr_var = nr_type_pdos(port->snk_pdo,
> -				    port->nr_snk_pdo,
> -				    PDO_TYPE_VAR);
> -	port->nr_batt = nr_type_pdos(port->snk_pdo,
> -				     port->nr_snk_pdo,
> -				     PDO_TYPE_BATT);
>  	port->nr_snk_vdo = tcpm_copy_vdos(port->snk_vdo, tcpc->config-
> >snk_vdo,
>  					  tcpc->config->nr_snk_vdo);
> 
> --
> 2.14.3
> 
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