From: Dan Williams
> Before we add another 2 bitfields to the port state, convert it to an
> unsigned long and use bitops helpers to manipulate it. This later
> enables setting bits to request action without worrying about colliding
> updates. In particular, a flag to request that the child device be
> woken up when the port restores power is added in a later patch.
...
> struct usb_port {
> struct usb_device *child;
> @@ -96,8 +95,9 @@ struct usb_port {
> enum usb_port_connect_type connect_type;
> usb_port_location_t location;
> u8 portnum;
> - unsigned power_is_on:1;
> - unsigned did_runtime_put:1;
> + #define USB_PORTDEV_POWER 0
> + #define USB_PORTDEV_DID_RUNTIME_PUT 1
> + unsigned long flags;
> };
...
An alternative is to 'waste' 7 bits and use byte-sized fields
for the separate flags.
I doubt the size of the data structure matters.
(Or do we have to worry about cpus that use RMW cycles for byte writes?)
David
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