Hi Tedd, > This patch enables autosuspend for Intel Bluetooth device. > > After btusb is loaded for Intel Bluetooth device, the power/control > attribute contains "on" value by default which disables the autosuspend. > Based on the USB PM document(Documentation/usb/power-management.txt), > kernel disabled the autosuspend for all devices other than hub by default. > > "The USB specification states that all USB devices must support power > management. Nevertheless, the sad fact is that many devices do not > support it very well. You can suspend them all right, but when you > try to resume them they disconnect themselves from the USB bus or > they stop working entirely. This seems to be especially prevalent > among printers and scanners, but plenty of other types of device have > the same deficiency. > > For this reason, by default the kernel disables autosuspend (the > power/control attribute is initialized to "on") for all devices other > than hubs. Hubs, at least, appear to be reasonably well-behaved in > this regard." > > This document also described how the driver can enables the autosuspend > by using an USB api. > > "Drivers can enable autosuspend for their devices by calling > > usb_enable_autosuspend(struct usb_device *udev); > > in their probe() routine, if they know that the device is capable of > suspending and resuming correctly. This is exactly equivalent to > writing "auto" to the device's power/control attribute." > > For Intel Bluetooth device, the autosuspend needs to be enabled so the > device can transit to LPM(Low Power Mode) and ULPM(Ultra LPM) states after > receiving suspend message from the host. > > Signed-off-by: Tedd Ho-Jeong An <tedd.an@xxxxxxxxx> > --- > drivers/bluetooth/btusb.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) patch has been applied to bluetooth-next tree. Regards Marcel -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
