Re: [PATCH RESEND2] net: stmmac: Fix unset max_speed difference between DT and non-DT platforms

From: Jakub Kicinski <kuba@kernel.org>
To: Chen-Yu Tsai <wens@kernel.org>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	"David S. Miller" <davem@davemloft.net>,
	Paolo Abeni <pabeni@redhat.com>, Chen-Yu Tsai <wens@csie.org>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Russell King <rmk+kernel@armlinux.org.uk>
Subject: Re: [PATCH RESEND2] net: stmmac: Fix unset max_speed difference between DT and non-DT platforms
Date: Fri, 1 Apr 2022 21:41:58 -0700	[thread overview]
Message-ID: <20220401214158.7346bd62@kernel.org> (raw)
In-Reply-To: <20220331184832.16316-1-wens@kernel.org>

On Fri,  1 Apr 2022 02:48:32 +0800 Chen-Yu Tsai wrote:
> From: Chen-Yu Tsai <wens@csie.org>
> 
> In commit 9cbadf094d9d ("net: stmmac: support max-speed device tree
> property"), when DT platforms don't set "max-speed", max_speed is set to
> -1; for non-DT platforms, it stays the default 0.
> 
> Prior to commit eeef2f6b9f6e ("net: stmmac: Start adding phylink support"),
> the check for a valid max_speed setting was to check if it was greater
> than zero. This commit got it right, but subsequent patches just checked
> for non-zero, which is incorrect for DT platforms.
> 
> In commit 92c3807b9ac3 ("net: stmmac: convert to phylink_get_linkmodes()")
> the conversion switched completely to checking for non-zero value as a
> valid value, which caused 1000base-T to stop getting advertised by
> default.
> 
> Instead of trying to fix all the checks, simply leave max_speed alone if
> DT property parsing fails.
> 
> Fixes: 9cbadf094d9d ("net: stmmac: support max-speed device tree property")
> Fixes: 92c3807b9ac3 ("net: stmmac: convert to phylink_get_linkmodes()")
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---
> 
> Resend2: CC Srinivas at Linaro instead of ST. Collected Russell's ack.
> Resend: added Srinivas (author of first fixed commit) to CC list.
> 
> This was first noticed on ROC-RK3399-PC, and also observed on ROC-RK3328-CC.
> The fix was tested on ROC-RK3328-CC and Libre Computer ALL-H5-ALL-CC.

This patch got marked Changes Requested in pw, but I can't see why, 
so I went on a limb and applied it. LMK if that was a mistake,
otherwise its commit c21cabb0fd0b ("net: stmmac: Fix unset max_speed
difference between DT and non-DT platforms") in net.