From: Andrew Lunn <andrew@lunn.ch>
To: Yongzhao Chen <yongzhao.derek@gmail.com>
Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Florian Fainelli <florian.fainelli@broadcom.com>,
Vladimir Oltean <olteanv@gmail.com>,
Christian Marangi <ansuelsmth@gmail.com>,
Heiner Kallweit <hkallweit1@gmail.com>,
Russell King <linux@armlinux.org.uk>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Ziyang Huang <hzyitc@outlook.com>
Subject: Re: [RFC PATCH net-next v3 4/5] net: dsa: qca8k: flag QCA8337 internal CPU PHYs for SmartSpeed
Date: Thu, 24 Sep 2026 04:51:05 +0200 [thread overview]
Message-ID: <09d669ff-7aad-4414-880a-21c2e7bf2cd7@lunn.ch> (raw)
In-Reply-To: <20260923215858.1653-5-yongzhao.derek@gmail.com>
On Wed, Sep 23, 2026 at 11:58:56PM +0200, Yongzhao Chen wrote:
> Flag QCA8337 internal PHYs used as CPU links for SmartSpeed suppression.
> SmartSpeed is the Qualcomm PHY driver downshift feature configured in
> register 0x14.
As far as i can see, nothing configures register 0x14, so this is not
very useful.
Please look at other PHYs which support downshift. There is a tunable
for it. Also, the read_status is expected to return the real speed,
which often is not in BMSR, but in a vendor register.
Is there an errata which covers this?
It would be interesting to know if downshift is broken in general, or
only when used in switch integrated PHYs.
What might be possible here it to look at phydev->is_internal, rather
than add a flag, to differentiate switch internal PHYs and discrete
PHYs.
Andrew
next prev parent reply other threads:[~2026-09-24 2:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-23 21:58 [RFC PATCH net-next v3 0/5] net: dsa: qca8k: add a QCA8337 CPU PHY consumer Yongzhao Chen
2026-09-23 21:58 ` [RFC PATCH net-next v3 1/5] net: dsa: pass PHY flags when connecting shared ports Yongzhao Chen
2026-09-23 21:58 ` [RFC PATCH net-next v3 2/5] net: dsa: qca8k: serialize CPU MAC pause during MTU changes Yongzhao Chen
2026-09-23 21:58 ` [RFC PATCH net-next v3 3/5] net: dsa: qca8k: support QCA8337 internal PHY CPU links Yongzhao Chen
2026-09-23 21:58 ` [RFC PATCH net-next v3 4/5] net: dsa: qca8k: flag QCA8337 internal CPU PHYs for SmartSpeed Yongzhao Chen
2026-09-24 2:51 ` Andrew Lunn [this message]
2026-09-24 23:48 ` Yongzhao Chen
2026-09-23 21:58 ` [RFC PATCH net-next v3 5/5] net: phy: qca83xx: disable SmartSpeed before resetting CPU PHYs Yongzhao Chen
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