Re: [PATCH] Input: xpad - power off wireless 360 controllers on suspend

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Wed, Jul 27, 2016 at 02:32:22PM -0700, Dmitry Torokhov wrote:
> On Mon, Jul 25, 2016 at 10:35:08PM -0700, Cameron Gutman wrote:
> > When the USB wireless adapter is suspended, the controllers
> > lose their connection. This causes them to start flashing
> > their LED rings and searching for the wireless adapter
> > again, wasting the controller's battery power.
> > 
> > Instead, we will tell the controllers to power down when
> > we suspend. This mirrors the behavior of the controllers
> > when connected to the console itself and how the official
> > Xbox One wireless adapter behaves on Windows.
> > 
> > Signed-off-by: Cameron Gutman <aicommander@gmail.com>
> > ---
> > This patch is independent of the other xpad patch [0] that I
> > submitted (and decided to wait on). It applies against
> > unmodified xpad.c in master.
> > 
> > [0] http://www.spinics.net/lists/linux-input/msg46062.html
> > ---
> >  drivers/input/joystick/xpad.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 43 insertions(+)
> > 
> > diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
> > index a529a45..3408019 100644
> > --- a/drivers/input/joystick/xpad.c
> > +++ b/drivers/input/joystick/xpad.c
> > @@ -115,6 +115,10 @@ static bool sticks_to_null;
> >  module_param(sticks_to_null, bool, S_IRUGO);
> >  MODULE_PARM_DESC(sticks_to_null, "Do not map sticks at all for unknown pads");
> >  
> > +static bool disable_auto_poweroff;
> > +module_param(disable_auto_poweroff, bool, S_IRUGO);
> > +MODULE_PARM_DESC(disable_auto_poweroff, "Do not power off wireless controllers on suspend");
> 
> Why negating? Why not do
> 
> static bool xpad_auto_poweroff = true;
> 
> ?
> 
> (No need to resubmit if agree/disagree, I can fix up on my side).

By the way, I think we can allow root writing to it, there is nothing
that stops us from changing behavior at runtime.

> 
> > +
> >  static const struct xpad_device {
> >  	u16 idVendor;
> >  	u16 idProduct;
> > @@ -1248,6 +1252,36 @@ static void xpad_stop_input(struct usb_xpad *xpad)
> >  	usb_kill_urb(xpad->irq_in);
> >  }
> >  
> > +static void xpad360w_poweroff_controller(struct usb_xpad *xpad)
> > +{
> > +	unsigned long flags;
> > +	struct xpad_output_packet *packet =
> > +			&xpad->out_packets[XPAD_OUT_CMD_IDX];
> > +
> > +	spin_lock_irqsave(&xpad->odata_lock, flags);
> > +
> > +	packet->data[0] = 0x00;
> > +	packet->data[1] = 0x00;
> > +	packet->data[2] = 0x08;
> > +	packet->data[3] = 0xC0;
> > +	packet->data[4] = 0x00;
> > +	packet->data[5] = 0x00;
> > +	packet->data[6] = 0x00;
> > +	packet->data[7] = 0x00;
> > +	packet->data[8] = 0x00;
> > +	packet->data[9] = 0x00;
> > +	packet->data[10] = 0x00;
> > +	packet->data[11] = 0x00;
> > +	packet->len = 12;
> > +	packet->pending = true;
> 
> I wonder of we don't want to convert commands to something like that:
> 
> 	static const u8 power_off_cmd[] = {
> 		0x00, 0x00, 0x08, 0xc0, 0x00, 0x00, 0x00, 0x00,
> 		0x00, 0x00, 0x00, 0x00,
> 	};
> 
> 	...
> 
> 	memcpy(packet->data, power_off_cmd, sizeof(power_off_cmd));
> 	// if we need to change something
> 	// packet->data[3] += command;
> 	// packet->data[6] = id;
> 	packet->len = sizeof(power_off_cmd);
> 	...
> 
> This should be a separate patch though.
> 
> Thanks.
> 
> -- 
> Dmitry

-- 
Dmitry