Messages in this thread | | | From | "Yang, Wenyou" <> | Subject | RE: [PATCH v3 1/2] usb: ohci-at91: Forcibly suspend ports while USB suspend | Date | Fri, 10 Jun 2016 08:58:41 +0000 |
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Hi Alan,
> -----Original Message----- > From: Alan Stern [mailto:stern@rowland.harvard.edu] > Sent: 2016年6月9日 3:14 > To: Yang, Wenyou <Wenyou.Yang@atmel.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Ferre, Nicolas > <Nicolas.FERRE@atmel.com>; Rob Herring <robh+dt@kernel.org>; Pawel Moll > <pawel.moll@arm.com>; Mark Brown <broonie@kernel.org>; Ian Campbell > <ijc+devicetree@hellion.org.uk>; Kumar Gala <galak@codeaurora.org>; > Alexandre Belloni <alexandre.belloni@free-electrons.com>; Kernel development > list <linux-kernel@vger.kernel.org>; devicetree@vger.kernel.org; linux-arm- > kernel@lists.infradead.org; USB list <linux-usb@vger.kernel.org> > 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 <wenyou.yang@atmel.com> > > --- > > 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
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