netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Baruch Siach <baruch@tkos.co.il>
To: Marek Behun <marek.behun@nic.cz>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	netdev@vger.kernel.org,
	Denis Odintsov <d.odintsov@traviangames.com>,
	Hubert Feurstein <h.feurstein@gmail.com>
Subject: Re: [BUG] mv88e6xxx: tx regression in v5.3
Date: Sun, 15 Dec 2019 13:10:19 +0200	[thread overview]
Message-ID: <871rt5u9no.fsf@tarshish> (raw)
In-Reply-To: <8736dlucai.fsf@tarshish>

Hi Marek,

On Sun, Dec 15 2019, Baruch Siach wrote:
> The call to mv88e6341_port_set_cmode() introduced in commit 7a3007d22e8
> ("net: dsa: mv88e6xxx: fully support SERDES on Topaz family") still
> breaks port 5 (cpu) configuration. When called, its mode parameter is
> set to PHY_INTERFACE_MODE_2500BASEX (19).
>
> Any idea?

I dug a little further here. It turns out that
mv88e6xxx_port_set_cmode() does not do any register write, because it
exits early here with cmode == 0xb:

        /* cmode doesn't change, nothing to do for us */
        if (cmode == chip->ports[port].cmode)
                return 0;

mv88e6341_port_set_cmode_writable() breaks the port configuration with
its call to mv88e6xxx_port_hidden_write(). Before this call
mv88e6352_port_get_cmode() sets cmode to 0xb. After this call cmode is
6. This breaks the assumption that the equality test above relies on.

This fixes cpu port configuration for me:

diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index 7fe256c5739d..a6c320978bcf 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -427,10 +427,6 @@ static int mv88e6xxx_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
 		cmode = 0;
 	}
 
-	/* cmode doesn't change, nothing to do for us */
-	if (cmode == chip->ports[port].cmode)
-		return 0;
-
 	lane = mv88e6xxx_serdes_get_lane(chip, port);
 	if (lane) {
 		if (chip->ports[port].serdes_irq) {

Does that make sense?

Thanks,
baruch

--
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch@tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -

  reply	other threads:[~2019-12-15 11:10 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-11  9:48 [BUG] mv88e6xxx: tx regression in v5.3 Baruch Siach
2019-12-11 13:11 ` Andrew Lunn
2019-12-11 17:07   ` Baruch Siach
2019-12-11 17:49     ` Andrew Lunn
2019-12-12  8:50       ` Baruch Siach
2019-12-12 13:14         ` Andrew Lunn
2019-12-12 14:19           ` Andreas Tobler
2019-12-12 15:08           ` Baruch Siach
2019-12-12 15:13             ` Andrew Lunn
2019-12-12 15:23               ` Baruch Siach
2019-12-12 18:17                 ` Baruch Siach
2019-12-12 18:32                   ` Marek Behun
2019-12-12 18:48                     ` Baruch Siach
2019-12-12 18:36                 ` Marek Behun
2019-12-12 19:06                   ` Baruch Siach
2019-12-12 19:31                     ` Andrew Lunn
2019-12-12 19:41                       ` Marek Behun
2019-12-12 20:49                         ` Andrew Lunn
2019-12-15 10:13                         ` Baruch Siach
2019-12-15 11:10                           ` Baruch Siach [this message]
2019-12-15 14:53                             ` Andrew Lunn
2019-12-15 15:08                               ` Baruch Siach
2019-12-15 16:14                                 ` Andrew Lunn
2019-12-17 18:26                                   ` Baruch Siach
2019-12-18 14:30                           ` Marek Behún
2019-12-18 16:04                             ` Baruch Siach
2019-12-19  9:04                             ` Baruch Siach

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=871rt5u9no.fsf@tarshish \
    --to=baruch@tkos.co.il \
    --cc=andrew@lunn.ch \
    --cc=d.odintsov@traviangames.com \
    --cc=h.feurstein@gmail.com \
    --cc=marek.behun@nic.cz \
    --cc=netdev@vger.kernel.org \
    --cc=vivien.didelot@gmail.com \
    /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).