On Wed, Jan 30, 2019 at 11:13:53AM +0800, Kyle Tso wrote: > When Sink negotiates PPS, the voltage range of selected PPS APDO might > not cover the previous voltage (out_volt). If the previous out_volt is > lower than the new min_volt, the output voltage in RDO might be set to > an invalid value. For instance, supposed that the previous voltage is > 5V, and the new voltage range in the APDO is 7V-12V. Then the output > voltage in the RDO should not be set to 5V which is lower than the > possible min_volt 7V. > > Fix this by choosing the maximal value between the previous voltage and > the new min_volt first. And ensure that this value will not exceed the > new max_volt. The new out_volt will fall within the new voltage range > while being the closest value compared to the previous out_volt. > > Signed-off-by: Kyle Tso <kyletso@xxxxxxxxxx> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> > --- > drivers/usb/typec/tcpm/tcpm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index f1d3e54210df..8f2af348bda5 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -2297,7 +2297,8 @@ static unsigned int tcpm_pd_select_pps_apdo(struct tcpm_port *port) > pdo_pps_apdo_max_voltage(snk)); > port->pps_data.max_curr = min_pps_apdo_current(src, snk); > port->pps_data.out_volt = min(port->pps_data.max_volt, > - port->pps_data.out_volt); > + max(port->pps_data.min_volt, > + port->pps_data.out_volt)); > port->pps_data.op_curr = min(port->pps_data.max_curr, > port->pps_data.op_curr); > } > -- > 2.20.1.495.gaa96b0ce6b-goog >
