RE: [PATCH] usb: typec: tcpm: Fix sink PDO starting index for PPS APDO selection

[Adam Thomson]

On 20 July 2018 15:40, Greg Kroah-Hartman wrote:

> On Fri, Jul 20, 2018 at 02:16:33PM +0000, Adam Thomson wrote:
> > On 20 July 2018 14:59, Greg Kroah-Hartman wrote:
> >
> > > On Tue, Jul 17, 2018 at 03:36:19PM +0100, Adam Thomson wrote:
> > > > There is a bug in the sink PDO search code when trying to select
> > > > a PPS APDO. The current code actually sets the starting index for
> > > > searching to whatever value 'i' is, rather than choosing index 1
> > > > to avoid the first PDO (always 5V fixed). As a result, for sources
> > > > which support PPS but whose PPS APDO index does not match with the
> > > > supporting sink PPS APDO index for the platform, no valid PPS APDO
> > > > will be found so this feature will not be permitted.
> > > >
> > > > Sadly in testing, both Source and Sink capabilities matched up and
> > > > this was missed. Code is now updated to correctly set the start
> > > > index to 1, and testing with additional PPS capable sources show
> > > > this to work as expected.
> > > >
> > > > Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>
> > > > ---
> > > >  drivers/usb/typec/tcpm.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> > > > index 74e0cda..4f1f421 100644
> > > > --- a/drivers/usb/typec/tcpm.c
> > > > +++ b/drivers/usb/typec/tcpm.c
> > > > @@ -2238,7 +2238,7 @@ static unsigned int tcpm_pd_select_pps_apdo(struct
> > > tcpm_port *port)
> > > >  			 * PPS APDO. Again skip the first sink PDO as this will
> > > >  			 * always be 5V 3A.
> > > >  			 */
> > > > -			for (j = i; j < port->nr_snk_pdo; j++) {
> > > > +			for (j = 1; j < port->nr_snk_pdo; j++) {
> > > >  				pdo = port->snk_pdo[j];
> > > >
> > > >  				switch (pdo_type(pdo)) {
> > >
> > > What commit id does this "fix"?
> > >
> > > Does it need to go into 4.18-final?  To the stable kernels?
> >
> > Sorry, missed that info. This fixes commit:
> >
> > 2eadc33f40d4c59dd0649f8b6958872d85ad05d7
> > 'typec: tcpm: Add core support for sink side PPS'
> >
> > This patch only went into v4.18-rc1 so should only be targeted for v4.18-final.
> >
> > Do you want me to resend with this information added?
> 
> It's ok, this time, I'll go hand-edit it...

Thanks :)