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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Trent Piepho <tpiepho@kymetacorp.com>
Cc: barebox <barebox@lists.infradead.org>
Subject: Re: [PATCH v3] net: designware: Don't hang in reset with powered down phy
Date: Fri, 13 Nov 2015 08:06:00 +0100	[thread overview]
Message-ID: <20151113070600.GX8526@pengutronix.de> (raw)
In-Reply-To: <1447275243.4553.119.camel@rtred1test09.kymeta.local>

On Wed, Nov 11, 2015 at 08:54:01PM +0000, Trent Piepho wrote:
> The dw MAC requires that all clock domains to be running for it to
> finish a MAC reset.  This include the clock provided by the PHY.
> 
> If the PHY is powered down, bit BMCR_PDOWN set, then it won't be
> generating a clock.  And so the MAC never comes out of reset.  On
> shutdown, Linux will put the PHY in powerdown mode, so it can easily
> be the case that the PHY is powered down on boot.
> 
> See Linux kernel commit 2d871aa07136fe6e576bde63072cf33e2c664e95.
> 
> Currently the MAC reset is done before the phy is probed.  We can't
> power up the phy until it's probed, so the resets must be in the
> opposite order.  The MAC reset is in device init but the PHY probe is
> in device open.  Device init is done first, always, while open is done
> later, and only if the device is used.
> 
> Rather than move the phy probe to init, this moves the MAC reset to
> open.  It seems better to speed up boots that doesn't use ethernet by
> skipping MAC reset than to slow them down by adding PHY probe.
> 
> Signed-off-by: Trent Piepho <tpiepho@kymetacorp.com>
> ---
> 
> Ignore v2, I missed a bunch of compiler warnings that scrolled off the
> screen and barebox doesn't seem to be using -Werror.

Newer compilers tend to introduce more warnings, so using -Werror would
mean that an older barebox will likely not build with recent compiler
versions. I had this problem with other projects sometimes, so I don't
think that using -Werror is a good idea.

Anyway, applied, thanks

Sascha


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      reply	other threads:[~2015-11-13  7:06 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-10 22:44 [PATCH] " Trent Piepho
2015-11-11  8:03 ` Sascha Hauer
2015-11-11 19:30   ` [PATCH v2] " Trent Piepho
2015-11-11 20:54     ` [PATCH v3] " Trent Piepho
2015-11-13  7:06       ` Sascha Hauer [this message]

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