Hi Alan, > -----Original Message----- > From: Alan Stern [mailto:[email protected]] > Sent: 2016年6月9日 3:14 > To: Yang, Wenyou <[email protected]> > Cc: Greg Kroah-Hartman <[email protected]>; Ferre, Nicolas > <[email protected]>; Rob Herring <[email protected]>; Pawel Moll > <[email protected]>; Mark Brown <[email protected]>; Ian Campbell > <[email protected]>; Kumar Gala <[email protected]>; > Alexandre Belloni <[email protected]>; Kernel development > list <[email protected]>; [email protected]; linux-arm- > [email protected]; USB list <[email protected]> > Subject: Re: [PATCH v3 1/2] usb: ohci-at91: Forcibly suspend ports while USB > suspend > > On Wed, 8 Jun 2016, Wenyou Yang wrote: > > > In order to the save power consumption, as a workaround, suspend > > forcibly the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI > > Interrupt Configuration Register in the SFRs while OHCI USB suspend. > > > > This suspend operation must be done before the USB clock is disabled, > > resume after the USB clock is enabled. > > > > Signed-off-by: Wenyou Yang <[email protected]> > > --- > > You never answered the questions I posted for the first version of this > patch: > > What does this mean? What does suspending a port do? Is it the same as a > normal USB port suspend? > > If it is the same, why doesn't the USB_PORT_FEAT_SUSPEND subcase of the > SetPortFeature case in ohci_hub_control() already take care of this?
I remembered I answered your questions, http://lists.infradead.org/pipermail/linux-arm-kernel/2016-May/429245.html Maybe not very clear. > > Alan Stern Best Regards, Wenyou Yang
