From a02dcd3b616ac481993efebde1bebb8529eea10c Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Fri, 14 Mar 2025 16:20:00 +0200 Subject: [PATCH] usb: hub: Fail fast in USB3 link power management enable path Enabling LPM is done in hub workqueue, often in paths handling possible link issues. So fail immediately on USB3 LPM issues and avoid hub wq from unnecessary blocking, thus allowing it to handle other port events faster. Detect errors when enabling U1/U2 link states, and return immediately if there is an issue. Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20250314142000.93090-6-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index e3929c0cd067..cfb3abafeacd 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4292,7 +4292,7 @@ static bool usb_device_may_initiate_lpm(struct usb_device *udev, * driver know about it. If that call fails, it should be harmless, and just * take up more slightly more bus bandwidth for unnecessary U1/U2 exit latency. */ -static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev, +static int usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev, enum usb3_link_state state) { int timeout; @@ -4301,7 +4301,7 @@ static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev, /* Skip if the device BOS descriptor couldn't be read */ if (!udev->bos) - return; + return -EINVAL; u1_mel = udev->bos->ss_cap->bU1devExitLat; u2_mel = udev->bos->ss_cap->bU2DevExitLat; @@ -4312,7 +4312,7 @@ static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev, */ if ((state == USB3_LPM_U1 && u1_mel == 0) || (state == USB3_LPM_U2 && u2_mel == 0)) - return; + return -EINVAL; /* We allow the host controller to set the U1/U2 timeout internally * first, so that it can change its schedule to account for the @@ -4323,13 +4323,13 @@ static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev, /* xHCI host controller doesn't want to enable this LPM state. */ if (timeout == 0) - return; + return -EINVAL; if (timeout < 0) { dev_warn(&udev->dev, "Could not enable %s link state, " "xHCI error %i.\n", usb3_lpm_names[state], timeout); - return; + return timeout; } if (usb_set_lpm_timeout(udev, state, timeout)) { @@ -4338,13 +4338,15 @@ static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev, * host know that this link state won't be enabled. */ hcd->driver->disable_usb3_lpm_timeout(hcd, udev, state); - return; + return -EBUSY; } if (state == USB3_LPM_U1) udev->usb3_lpm_u1_enabled = 1; else if (state == USB3_LPM_U2) udev->usb3_lpm_u2_enabled = 1; + + return 0; } /* * Disable the hub-initiated U1/U2 idle timeouts, and disable device-initiated @@ -4497,10 +4499,12 @@ void usb_enable_lpm(struct usb_device *udev) port_dev = hub->ports[udev->portnum - 1]; if (port_dev->usb3_lpm_u1_permit) - usb_enable_link_state(hcd, udev, USB3_LPM_U1); + if (usb_enable_link_state(hcd, udev, USB3_LPM_U1)) + return; if (port_dev->usb3_lpm_u2_permit) - usb_enable_link_state(hcd, udev, USB3_LPM_U2); + if (usb_enable_link_state(hcd, udev, USB3_LPM_U2)) + return; /* * Enable device initiated U1/U2 with a SetFeature(U1/U2_ENABLE) request -- 2.25.1