Re: Re: [PATCH] net: dwmac-rk: MAC clock should be truned off

[Andrew Lunn <andrew@lunn.ch>]

On Sat, May 24, 2025 at 10:05:47PM +0800, lizhe wrote:
> Hi， Anerdw
> The following is the logic for calling this function： 
> 
> 
> rk_gmac_powerup() {
> 
> ret = phy_power_on(bsp_priv, true);      // here.
> 
> if (ret) {
> 
> gmac_clk_enable(bsp_priv, false);
> 
> return ret;
> 
> }
> 
> }

Ah, there is something funny with your patch. Look at the diff:

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
index 700858ff6f7c..036e45be5828 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
@@ -1648,7 +1648,7 @@  static int gmac_clk_enable(struct rk_priv_data *bsp_priv, bool enable)

This line tells you where in the file you are patching, and the
function to be patched. This is what i looked at,
gmac_clk_enable(). And gmac_clk_enable() has a similar structure, ret
declared at the beginning, return 0 at the end. But the only way to
that return 0 is without error.

But patch is actually for:

 static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
 {
 	struct regulator *ldo = bsp_priv->regulator;
-	int ret;
+	int ret = 0;
 	struct device *dev = &bsp_priv->pdev->dev;
 
 	if (enable) {
@@ -1661,7 +1661,7 @@  static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
 			dev_err(dev, "fail to disable phy-supply\n");
 	}
 
-	return 0;
+	return ret;
 }

And agree, the error codes are ignored in phy_power_on().

But i have a few questions:

How did you generate this diff? This is the first time i've made this
mistake, as far as i know. I trust the context information when
reviewing patches. Yet here it is wrong. Why? Is this actually normal?
I know diff gets it wrong for python, i don't trust it at all with
that language, but i've not noticed such problems with C.

Did you look at the history of phy_power_on()? It looks pretty
deliberate ignoring errors. Maybe there is a reason why this happens?
git blame and git log might explain why it is like this.

	Andrew