From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Lunn <andrew@lunn.ch>,
Heiner Kallweit <hkallweit1@gmail.com>,
netdev <netdev@vger.kernel.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: PHY reset may still be asserted during MDIO probe
Date: Fri, 9 Jul 2021 16:54:44 +0100 [thread overview]
Message-ID: <20210709155444.GB22278@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAMuHMdXno2OUHqsAfO0z43JmGkFehD+FJ2dEjEsr_P53oAAPxA@mail.gmail.com>
On Fri, Jul 09, 2021 at 05:33:36PM +0200, Geert Uytterhoeven wrote:
> Hi all,
>
> I'm investigating a network failure after kexec on the Renesas Koelsch
> and Salvator-XS development boards, using the sh-eth or ravb driver.
Personally, I've never liked the reset support at PHY device level due
to problems like the one you've identified here. I've tended to use the
bus-level reset in preference to the PHY-level reset, particularly
because when you have multiple PHYs on the bus all sharing a common
reset, it seems to be the most sensible approach - and I see a single
PHY as no different from multiple PHYs on the bus.
However, I can see the argument for using the PHY level, but as you
note, that can create chicken and egg issues. I'm not entirely sure
why we decide to hold a PHY in reset when we've found it but not
started to make use of it - we don't do that with other devices in
the system. Why are PHYs special?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2021-07-09 15:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-09 15:33 PHY reset may still be asserted during MDIO probe Geert Uytterhoeven
2021-07-09 15:54 ` Russell King (Oracle) [this message]
2021-07-09 16:22 ` Andrew Lunn
2021-07-09 18:14 ` Grygorii Strashko
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