Dave:
Right now my development patches make all the autosuspend stuff
conditional on CONFIG_USB_SUSPEND. There didn't seem to be much point
including code to submit automatic suspend requests if usbcore wasn't
going to actually suspend the devices!
But what about root hubs? For ehci-hcd it's a non-issue (the current code
never automatically suspends the root hub) and uhci-hcd includes its own
auto-stop facility. However ohci-hcd has a peculiar hybrid kind of
autosuspend facility built in, which cooperates rather awkwardly with the
rest of the USB subsystem. (I'm referring to things like
usb_hcd_suspend_root_hub(), which is called only from ohci-hub.c.) One of
my patches removes it, on the theory that it isn't needed since the core
will now handle autosuspending.
This leaves open the question of suspending OHCI controllers when
CONFIG_USB_SUSPEND is not set.
Should we figure that CONFIG_USB_SUSPEND will be removed
eventually (made permanently true) so this doesn't matter?
Should I simply not worry about it? Let the OHCI root hubs
keep running?
Should I make the autosuspend code conditional on CONFIG_PM
instead of CONFIG_USB_SUSPEND?
Do you want to change ohci-hcd, giving it a simple "auto-stop"
facility like the one in uhci-hcd rather than an idiosyncratic
autosuspend?
Alan Stern
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