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From: Alan Stern <stern@rowland.harvard.edu>
To: Julius Werner <jwerner@chromium.org>
Cc: Felipe Balbi <balbi@ti.com>,
	Douglas Anderson <dianders@chromium.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	John Youn <johnyoun@synopsys.com>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	Chris Zhong <zyw@rock-chips.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Andrew Bresticker <abrestic@chromium.org>,
	Alexandru Stan <amstan@chromium.org>, lyz <lyz@rock-chips.com>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [REPOST PATCH 3/3] USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled
Date: Wed, 8 Jul 2015 15:58:14 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1507081555570.2243-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <CAODwPW9-5abTDGwLyNRZ0hvn4+6T8ix55TqFhSy_xZx1VVuVNA@mail.gmail.com>

On Wed, 8 Jul 2015, Julius Werner wrote:

> > But I don't see how you will make it work when the root hub itself is
> > not enabled for wakeup and a non-hub device plugged into one of the
> > root hub's ports is enabled.
> >
> > It seems like you would need a usb_hcd_wakeup_not_needed(hcd, port)
> > subroutine.
> 
> We'd just put that in the Tegra platform driver, I guess. Iterate over
> all ports, call usb_wakeup_enabled_descendants() on the connected
> device (if any) and disable that port's PHY if it returns 0 or wasn't
> connected. Since usb_wakeup_enabled_descendants() also counts
> do_remote_wakeup from the device itself and is safe to call even on
> non-hubs, that should work for all cases.

All right, that seems reasonable.  But remember not to do this if 
wakeup is enabled on the root hub -- in that case all the PHYs must 
remain powered because unplugging and plugging are both wakeup events.

Alan Stern


WARNING: multiple messages have this Message-ID (diff)
From: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
To: Julius Werner <jwerner-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>,
	Douglas Anderson
	<dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Greg Kroah-Hartman
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	John Youn <johnyoun-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>,
	"linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Chris Zhong <zyw-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>,
	Andrew Bresticker
	<abrestic-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Alexandru Stan <amstan-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	lyz <lyz-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [REPOST PATCH 3/3] USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled
Date: Wed, 8 Jul 2015 15:58:14 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1507081555570.2243-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <CAODwPW9-5abTDGwLyNRZ0hvn4+6T8ix55TqFhSy_xZx1VVuVNA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Wed, 8 Jul 2015, Julius Werner wrote:

> > But I don't see how you will make it work when the root hub itself is
> > not enabled for wakeup and a non-hub device plugged into one of the
> > root hub's ports is enabled.
> >
> > It seems like you would need a usb_hcd_wakeup_not_needed(hcd, port)
> > subroutine.
> 
> We'd just put that in the Tegra platform driver, I guess. Iterate over
> all ports, call usb_wakeup_enabled_descendants() on the connected
> device (if any) and disable that port's PHY if it returns 0 or wasn't
> connected. Since usb_wakeup_enabled_descendants() also counts
> do_remote_wakeup from the device itself and is safe to call even on
> non-hubs, that should work for all cases.

All right, that seems reasonable.  But remember not to do this if 
wakeup is enabled on the root hub -- in that case all the PHYs must 
remain powered because unplugging and plugging are both wakeup events.

Alan Stern

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  reply	other threads:[~2015-07-08 19:58 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-06 18:27 [REPOST PATCH 0/3] dwc2 patches to allow wakeup on Rockchip rk3288 Douglas Anderson
2015-07-06 18:27 ` Douglas Anderson
2015-07-06 18:27 ` [REPOST PATCH 1/3] USB: Export usb_wakeup_enabled_descendants() Douglas Anderson
2015-07-06 18:27   ` Douglas Anderson
2015-07-06 18:27 ` [REPOST PATCH 2/3] Documentation: dt-bindings: Add snps,need-phy-for-wake for dwc2 USB Douglas Anderson
2015-07-06 18:27   ` Douglas Anderson
2015-07-06 18:27 ` [REPOST PATCH 3/3] USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled Douglas Anderson
2015-07-06 18:27   ` Douglas Anderson
2015-07-06 18:34   ` Felipe Balbi
2015-07-06 18:34     ` Felipe Balbi
2015-07-06 19:32     ` Doug Anderson
2015-07-06 19:32       ` Doug Anderson
2015-07-06 19:35       ` Felipe Balbi
2015-07-06 19:35         ` Felipe Balbi
2015-07-06 18:58   ` Alan Stern
2015-07-06 18:58     ` Alan Stern
2015-07-06 19:02     ` Felipe Balbi
2015-07-06 19:02       ` Felipe Balbi
2015-07-06 19:39       ` Doug Anderson
2015-07-06 19:39         ` Doug Anderson
2015-07-07 14:28       ` Alan Stern
2015-07-07 14:28         ` Alan Stern
2015-07-08  0:06         ` Julius Werner
2015-07-08  0:06           ` Julius Werner
2015-07-08 15:01           ` Alan Stern
2015-07-08 19:41             ` Julius Werner
2015-07-08 19:41               ` Julius Werner
2015-07-08 19:58               ` Alan Stern [this message]
2015-07-08 19:58                 ` Alan Stern
2015-10-21 16:23 ` [REPOST PATCH 0/3] dwc2 patches to allow wakeup on Rockchip rk3288 Doug Anderson
2015-10-21 16:23   ` Doug Anderson
2015-10-27  2:05   ` John Youn
2015-10-27  2:05     ` John Youn
2015-10-31  0:01     ` Doug Anderson
2015-10-31  0:01       ` Doug Anderson

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