Re: [PATCH] usb: typec: tcpm: Fix APDO PPS order checking to be based on voltage

From: Guenter Roeck
Date: Fri Sep 21 2018 - 11:52:30 EST


On Fri, Sep 21, 2018 at 04:04:11PM +0100, Adam Thomson wrote:
> Current code mistakenly checks against max current to determine
> order but this should be max voltage. This commit fixes the issue
> so order is correctly determined, thus avoiding failure based on
> a higher voltage PPS APDO having a lower maximum current output,
> which is actually valid.
>
> Fixes: 2eadc33f40d4 ("typec: tcpm: Add core support for sink side PPS")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>

Makes sense.

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

> ---
> Code based on usb-testing branch (ae8a2ca8a2215c7e31e6d874f7303801bb15fbb)
>
> drivers/usb/typec/tcpm/tcpm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 4f1f421..c11b3be 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -1430,8 +1430,8 @@ static enum pdo_err tcpm_caps_err(struct tcpm_port *port, const u32 *pdo,
> if (pdo_apdo_type(pdo[i]) != APDO_TYPE_PPS)
> break;
>
> - if (pdo_pps_apdo_max_current(pdo[i]) <
> - pdo_pps_apdo_max_current(pdo[i - 1]))
> + if (pdo_pps_apdo_max_voltage(pdo[i]) <
> + pdo_pps_apdo_max_voltage(pdo[i - 1]))
> return PDO_ERR_PPS_APDO_NOT_SORTED;
> else if (pdo_pps_apdo_min_voltage(pdo[i]) ==
> pdo_pps_apdo_min_voltage(pdo[i - 1]) &&
> --
> 1.9.1
>