From d49dad3e11638f66be4e16573ffaa8c46a09e3b3 Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Mon, 5 Aug 2013 18:58:15 -0700 Subject: [PATCH] usb: Don't fail port power resume on device disconnect. Userspace can tell the kernel to power off any USB port, including ones that are visible and connectible to users. When an attached USB device goes into suspend, the port will be powered off if the pm_qos_no_port_poweroff file for its port is set to 0, the device does not have remote wakeup enabled, and the device is marked as persistent. If the user disconnects the USB device while the port is powered off, the current code does not handle that properly. If you disconnect a device, and then run `lsusb -v -s` for the device, the device disconnect does not get handled by the USB core. The runtime resume of the port fails, because hub_port_debounce_be_connected() returns -ETIMEDOUT. This means the port resume fails and khubd doesn't handle the USB device disconnect. This leaves the device listed in lsusb, and the port's runtime_status will be permanently marked as "error". Fix this by ignoring the return value of hub_port_debounce_be_connected. Users can disconnect USB devices while the ports are powered off, and we must be able to handle that. This patch should be backported to kernels as old as 3.9, that contain the commit ad493e5e580546e6c3024b76a41535476da1546a "usb: add usb port auto power off mechanism" Signed-off-by: Sarah Sharp Cc: Lan Tianyu Cc: Alan Stern Cc: Rafael J. Wysocki Cc: stable@vger.kernel.org Signed-off-by: Sarah Sharp --- drivers/usb/core/port.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c index d6b0fad..9909911 100644 --- a/drivers/usb/core/port.c +++ b/drivers/usb/core/port.c @@ -89,22 +89,19 @@ static int usb_port_runtime_resume(struct device *dev) retval = usb_hub_set_port_power(hdev, hub, port1, true); if (port_dev->child && !retval) { /* - * Wait for usb hub port to be reconnected in order to make - * the resume procedure successful. + * Attempt to wait for usb hub port to be reconnected in order + * to make the resume procedure successful. The device may have + * disconnected while the port was powered off, so ignore the + * return status. */ retval = hub_port_debounce_be_connected(hub, port1); - if (retval < 0) { + if (retval < 0) dev_dbg(&port_dev->dev, "can't get reconnection after setting port power on, status %d\n", retval); - goto out; - } usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE); - - /* Set return value to 0 if debounce successful */ retval = 0; } -out: clear_bit(port1, hub->busy_bits); usb_autopm_put_interface(intf); return retval; -- 2.7.4