Hi Matthew,
> The usbhid autosuspend code refuses to suspend if there are any LEDs lit,
> in order to avoid situations where this would draw more power than
> available when suspended. The current implementation is a counter that's
> incremented on LED on and decremented on LED off. However, if a system
> suspend takes place, the input core will resynchronise state on resume by
> sending LED on and off requests. This may cause the counter to underflow,
> resulting in autosuspend being disabled for the rest of system uptime.
> This patch simply replaces the counter with a bitmask of the actual LED
> state in order to avoid this.
>
> Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx>
> ---
> drivers/hid/usbhid/hid-core.c | 6 +++---
> drivers/hid/usbhid/usbhid.h | 2 +-
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
> index ad978f5..fd96d38 100644
> --- a/drivers/hid/usbhid/hid-core.c
> +++ b/drivers/hid/usbhid/hid-core.c
> @@ -598,11 +598,11 @@ static int usb_hidinput_input_event(struct input_dev *dev, unsigned int type, un
> hid_set_field(field, offset, value);
> if (value) {
> spin_lock_irqsave(&usbhid->lock, flags);
> - usbhid->ledcount++;
> + usbhid->ledstate |= (1 << code);
To be consistent, ledstate should be a bitmask the same size as in
input_dev, but it aint pretty...
> spin_unlock_irqrestore(&usbhid->lock, flags);
> } else {
> spin_lock_irqsave(&usbhid->lock, flags);
> - usbhid->ledcount--;
> + usbhid->ledstate &= ~(1 << code);
Could simply check for ledcount > 0 here instead, but it is even uglier.
> spin_unlock_irqrestore(&usbhid->lock, flags);
> }
> usbhid_submit_report(hid, field->report, USB_DIR_OUT);
> @@ -1339,7 +1339,7 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message)
> && !test_bit(HID_OUT_RUNNING, &usbhid->iofl)
> && !test_bit(HID_CTRL_RUNNING, &usbhid->iofl)
> && !test_bit(HID_KEYS_PRESSED, &usbhid->iofl)
> - && (!usbhid->ledcount || ignoreled))
> + && (!usbhid->ledstate || ignoreled))
Why not test the actual input_dev state here instead? Adding a set/get
led state function to input core could resolve this cleanly.
> {
> set_bit(HID_REPORTED_IDLE, &usbhid->iofl);
> spin_unlock_irq(&usbhid->lock);
> diff --git a/drivers/hid/usbhid/usbhid.h b/drivers/hid/usbhid/usbhid.h
> index 1673cac..1d0e2bd 100644
> --- a/drivers/hid/usbhid/usbhid.h
> +++ b/drivers/hid/usbhid/usbhid.h
> @@ -96,7 +96,7 @@ struct usbhid_device {
> unsigned int retry_delay; /* Delay length in ms */
> struct work_struct reset_work; /* Task context for resets */
> wait_queue_head_t wait; /* For sleeping */
> - int ledcount; /* counting the number of active leds */
> + int ledstate; /* Bitmask of active LEDs */
> };
>
> #define hid_to_usb_dev(hid_dev) \
> --
> 1.7.6.4
Cheers,
Henrik
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