lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Sat, 30 May 2020 21:51:02 -0700 (PDT)
From:   David Miller <>
Subject: Re: [PATCH RFT] ravb: Mask PHY mode to avoid inserting delays twice

From: Geert Uytterhoeven <>
Date: Fri, 29 May 2020 14:25:40 +0200

> Until recently, the Micrel KSZ9031 PHY driver ignored any PHY mode
> ("RGMII-*ID") settings, but used the hardware defaults, augmented by
> explicit configuration of individual skew values using the "*-skew-ps"
> DT properties.  The lack of PHY mode support was compensated by the
> EtherAVB MAC driver, which configures TX and/or RX internal delay
> itself, based on the PHY mode.
> However, now the KSZ9031 driver has gained PHY mode support, delays may
> be configured twice, causing regressions.  E.g. on the Renesas
> Salvator-X board with R-Car M3-W ES1.0, TX performance dropped from ca.
> 400 Mbps to 0.1-0.3 Mbps, as measured by nuttcp.
> As internal delay configuration supported by the KSZ9031 PHY is too
> limited for some use cases, the ability to configure MAC internal delay
> is deemed useful and necessary.  Hence a proper fix would involve
> splitting internal delay configuration in two parts, one for the PHY,
> and one for the MAC.  However, this would require adding new DT
> properties, thus breaking DTB backwards-compatibility.
> Hence fix the regression in a backwards-compatibility way, by letting
> the EtherAVB driver mask the PHY mode when it has inserted a delay, to
> avoid the PHY driver adding a second delay.  This also fixes messages
> like:
>     Micrel KSZ9031 Gigabit PHY e6800000.ethernet-ffffffff:00: *-skew-ps values should be used only with phy-mode = "rgmii"
> as the PHY no longer sees the original RGMII-*ID mode.
> Solving the issue by splitting configuration in two parts can be handled
> in future patches, and would require retaining a backwards-compatibility
> mode anyway.
> Fixes: bcf3440c6dd78bfe ("net: phy: micrel: add phy-mode support for the KSZ9031 PHY")
> Signed-off-by: Geert Uytterhoeven <>

Applied to net-next, thank you.

Powered by blists - more mailing lists