Re: [PATCH 0/2] Reset realtek bluetooth devices during user suspend

From: Oliver Neukum
Date: Wed Sep 18 2019 - 10:41:35 EST


Am Dienstag, den 17.09.2019, 14:27 -0700 schrieb Abhishek Pandit-
Subedi:
> On a Realtek USB bluetooth device, I wanted a simple and consistent way
> to put the device in reset during suspend (2 reasons: to save power and

The device really uses less power if you reset it before suspendening
it?

> disable BT as a wakeup source). Resetting it in the suspend callback

Then do not enable it. Something is strange.

> causes a detach and the resume callback is not called. Hence the changes
> in this series to do the reset in suspend_noirq.
>
> I looked into using PERSIST and reset on resume but those seem mainly
> for misbehaving devices that reset themselves.

No, not really. It is also for device that need to be reset if you use
the RESET_RESUME quirk. But that is on resume().
You could introduce a new flag. But the _noirq method is kind of
a hack, as USB really cannot operate without interrupts.

Regards
Oliver