From: Andy Duan <fugang.duan@nxp.com>
To: David Miller <davem@davemloft.net>
Cc: "andrew@lunn.ch" <andrew@lunn.ch>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"cphealy@gmail.com" <cphealy@gmail.com>,
Leonard Crestez <leonard.crestez@nxp.com>
Subject: RE: [EXT] Re: [PATCH net-next] net: ethernet: fec: Prevent MII event after MII_SPEED write
Date: Wed, 29 Apr 2020 03:43:15 +0000 [thread overview]
Message-ID: <HE1PR0402MB2745963E2B675BAC95A61E55FFAD0@HE1PR0402MB2745.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20200428.203439.49635882087657701.davem@davemloft.net>
From: David Miller <davem@davemloft.net> Sent: Wednesday, April 29, 2020 11:35 AM
> From: Andy Duan <fugang.duan@nxp.com>
> Date: Wed, 29 Apr 2020 01:55:35 +0000
>
> > From: David Miller <davem@davemloft.net> Sent: Wednesday, April 29,
> > 2020 5:34 AM
> >> From: Andrew Lunn <andrew@lunn.ch>
> >> Date: Tue, 28 Apr 2020 19:58:33 +0200
> >>
> >> > The change to polled IO for MDIO completion assumes that MII events
> >> > are only generated for MDIO transactions. However on some SoCs
> >> > writing to the MII_SPEED register can also trigger an MII event. As
> >> > a result, the next MDIO read has a pending MII event, and
> >> > immediately reads the data registers before it contains useful
> >> > data. When the read does complete, another MII event is posted,
> >> > which results in the next read also going wrong, and the cycle continues.
> >> >
> >> > By writing 0 to the MII_DATA register before writing to the speed
> >> > register, this MII event for the MII_SPEED is suppressed, and
> >> > polled IO works as expected.
> >> >
> >> > Fixes: 29ae6bd1b0d8 ("net: ethernet: fec: Replace interrupt driven
> >> > MDIO with polled IO")
> >> > Reported-by: Andy Duan <fugang.duan@nxp.com>
> >> > Suggested-by: Andy Duan <fugang.duan@nxp.com>
> >> > Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> >>
> >> Applied to net-next, thanks.
> >
> > David, it is too early to apply the patch, it will introduce another
> > break issue as I explain in previous mail for the patch.
>
> So what should I do, revert?
If you can revert the patch, please do it.
Thanks, David.
next prev parent reply other threads:[~2020-04-29 3:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 17:58 [PATCH net-next] net: ethernet: fec: Prevent MII event after MII_SPEED write Andrew Lunn
2020-04-28 18:01 ` Andrew Lunn
2020-04-29 1:39 ` [EXT] " Andy Duan
2020-04-28 21:33 ` David Miller
2020-04-29 1:55 ` [EXT] " Andy Duan
2020-04-29 3:34 ` David Miller
2020-04-29 3:43 ` Andy Duan [this message]
2020-04-29 14:11 ` Andrew Lunn
2020-04-29 19:16 ` David Miller
2020-04-29 1:53 ` [EXT] " Andy Duan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=HE1PR0402MB2745963E2B675BAC95A61E55FFAD0@HE1PR0402MB2745.eurprd04.prod.outlook.com \
--to=fugang.duan@nxp.com \
--cc=andrew@lunn.ch \
--cc=cphealy@gmail.com \
--cc=davem@davemloft.net \
--cc=leonard.crestez@nxp.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).