Re: "asix: Don't reset PHY on if_up for ASIX 88772" breaks net onarndale platform

From: Riku Voipio <riku.voipio@iki.fi>
To: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Cc: "Stam, Michel [FINT]" <M.Stam@fugro.nl>,
	freddy@asix.com.tw, davem@davemloft.net,
	linux-usb@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org
Subject: Re: "asix: Don't reset PHY on if_up for ASIX 88772" breaks net onarndale platform
Date: Fri, 7 Nov 2014 10:44:49 +0200	[thread overview]
Message-ID: <20141107084449.GA11078@afflict.kos.to> (raw)
In-Reply-To: <20141106140940.GW23178@opensource.wolfsonmicro.com>

On Thu, Nov 06, 2014 at 02:09:40PM +0000, Charles Keepax wrote:
> On Thu, Nov 06, 2014 at 03:01:56PM +0100, Stam, Michel [FINT] wrote:
> > Hello Charles and Riku,
> > 
> > I've quickly tested this on a 3.10 kernel i had around;
> > I enabled CONFIG_PM, CONFIG_PM_RUNTIME, CONFIG_PM_AUTOSLEEP,
> > CONFIG_SUSPEND, CONFIG_SUSPEND_FREEZER, CONFIG_FREEZER in the kernel (by
> > default they are disabled for our setup, I enabled anything regarded to
> > runtime powermanagement to be sure I would trigger suspend/resume).
> > 
> > Then:
> > cd /sys/bus/usb/devices/1-2/power
> > echo auto > control
> > echo 1 > autosuspend
> > echo 0 > autosuspend_delay_ms
> > echo enabled > wakeup
> > 
> > # make sure there's no processes routing traffic over the eth1 interface
> > 
> > ifconfig eth1 down
> > sleep 4 # sleep some arbitrary long time
> > ifconfig eth1 up
> > 
> > check dmesg; it will reset back to 100 Mbps/full duplex.
> > 
> > This confirms that the suspend / resume does not work well. So long as
> > the suspend is not triggered, it does seem to work, though. I cannot say
> > whether the original issue that triggered this is still around; the ASIX
> > chip setup we use is soldered to the PCB and hooked up to a fixed device
> > on-board. 
> > I also tried to ping the device on the other side of the ASIX chip after
> > the suspend/resume cycle, I could not ping it. I cannot conclusively say
> > that this is due to the ASIX driver, as the device on the other side
> > does not like switching PHY speeds (it may go into a non-responsive
> > state). It is for this reason that we run it at half duplex/ 10Mbps at
> > all times.
> > 
> > As said; we are not using this kind of power management, so it does not
> > raise any issues for us. I am merely pointing out that this may need
> > work (in the future?).

> Cool thanks for checking this I will make a note in the commit
> message that suspend/resume might need some more work.

Thanks for digging through,

Make sure the commit message is clear that your patch is a regression
fix - following just this thread it might be a bit unclear.

Riku