From f3da3192cdd3fefe213390e976eec424a8e270b5 Mon Sep 17 00:00:00 2001 From: Kyle Tso Date: Thu, 4 Apr 2024 21:35:17 +0800 Subject: usb: typec: tcpm: Correct the PDO counting in pd_set commit c4128304c2169b4664ed6fb6200f228cead2ab70 upstream. Off-by-one errors happen because nr_snk_pdo and nr_src_pdo are incorrectly added one. The index of the loop is equal to the number of PDOs to be updated when leaving the loop and it doesn't need to be added one. When doing the power negotiation, TCPM relies on the "nr_snk_pdo" as the size of the local sink PDO array to match the Source capabilities of the partner port. If the off-by-one overflow occurs, a wrong RDO might be sent and unexpected power transfer might happen such as over voltage or over current (than expected). "nr_src_pdo" is used to set the Rp level when the port is in Source role. It is also the array size of the local Source capabilities when filling up the buffer which will be sent as the Source PDOs (such as in Power Negotiation). If the off-by-one overflow occurs, a wrong Rp level might be set and wrong Source PDOs will be sent to the partner port. This could potentially cause over current or port resets. Fixes: cd099cde4ed2 ("usb: typec: tcpm: Support multiple capabilities") Cc: stable@vger.kernel.org Signed-off-by: Kyle Tso Reviewed-by: Heikki Krogerus Link: https://lore.kernel.org/r/20240404133517.2707955-1-kyletso@google.com Signed-off-by: Greg Kroah-Hartman --- 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 f81699537312..df9a5d6760b4 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -6111,14 +6111,14 @@ static int tcpm_pd_set(struct typec_port *p, struct usb_power_delivery *pd) if (data->sink_desc.pdo[0]) { for (i = 0; i < PDO_MAX_OBJECTS && data->sink_desc.pdo[i]; i++) port->snk_pdo[i] = data->sink_desc.pdo[i]; - port->nr_snk_pdo = i + 1; + port->nr_snk_pdo = i; port->operating_snk_mw = data->operating_snk_mw; } if (data->source_desc.pdo[0]) { for (i = 0; i < PDO_MAX_OBJECTS && data->source_desc.pdo[i]; i++) port->src_pdo[i] = data->source_desc.pdo[i]; - port->nr_src_pdo = i + 1; + port->nr_src_pdo = i; } switch (port->state) { -- cgit v1.2.3