From 07c8d2a109d847775b3b4e2c3294c8e1eea75432 Mon Sep 17 00:00:00 2001 From: Mark Pearson Date: Thu, 21 Aug 2025 14:53:07 -0400 Subject: [PATCH] usb: typec: ucsi: Handle incorrect num_connectors capability [ Upstream commit 30cd2cb1abf4c4acdb1ddb468c946f68939819fb ] The UCSI spec states that the num_connectors field is 7 bits, and the 8th bit is reserved and should be set to zero. Some buggy FW has been known to set this bit, and it can lead to a system not booting. Flag that the FW is not behaving correctly, and auto-fix the value so that the system boots correctly. Found on Lenovo P1 G8 during Linux enablement program. The FW will be fixed, but seemed worth addressing in case it hit platforms that aren't officially Linux supported. Signed-off-by: Mark Pearson Reviewed-by: Heikki Krogerus Link: https://lore.kernel.org/r/20250821185319.2585023-1-mpearson-lenovo@squebb.ca Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/typec/ucsi/ucsi.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index 0851d93d59096..60339c7466941 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -1220,6 +1220,12 @@ static int ucsi_init(struct ucsi *ucsi) ret = -ENODEV; goto err_reset; } + /* Check if reserved bit set. This is out of spec but happens in buggy FW */ + if (ucsi->cap.num_connectors & 0x80) { + dev_warn(ucsi->dev, "UCSI: Invalid num_connectors %d. Likely buggy FW\n", + ucsi->cap.num_connectors); + ucsi->cap.num_connectors &= 0x7f; // clear bit and carry on + } /* Allocate the connectors. Released in ucsi_unregister_ppm() */ ucsi->connector = kcalloc(ucsi->cap.num_connectors + 1, -- 2.47.3