Re: [net-next,v2,01/12] net: phy: phy_port: Correctly recompute the port's linkmodes
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-01-30 04:00:11
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This is an AI-generated review of your patch. The human sending this email has considered the AI review valid, or at least plausible. For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html --- net: phy: phy_port: Correctly recompute the port's linkmodes This patch changes phy_port_update_supported() from OR'ing medium-specific modes into port->supported to AND'ing (filtering) port->supported against the accumulated medium modes. Fixes: 589e934d2735 ("net: phy: Introduce PHY ports representation")
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/phy/phy_port.c b/drivers/net/phy/phy_port.c index ec93c8ca051e..68a0068220ed 100644 --- a/drivers/net/phy/phy_port.c +++ b/drivers/net/phy/phy_port.c@@ -118,11 +118,14 @@ void phy_port_update_supported(struct phy_port *port) int i; for_each_set_bit(i, &port->mediums, __ETHTOOL_LINK_MEDIUM_LAST) { - linkmode_zero(supported); - phy_caps_medium_get_supported(supported, i, port->pairs); - linkmode_or(port->supported, port->supported, supported); + __ETHTOOL_DECLARE_LINK_MODE_MASK(med_supported) = {0}; + + phy_caps_medium_get_supported(med_supported, i, port->pairs); + linkmode_or(supported, supported, med_supported); } + linkmode_and(port->supported, port->supported, supported);
When port->supported starts empty (all zeros), this AND operation will always produce an empty result regardless of what modes are in supported. Tracing the call path of_phy_ports() -> phy_of_parse_port() -> phy_add_port() -> phy_port_update_supported(): phy_of_parse_port() creates the port via phy_port_alloc() which zeros port->supported, and phy_of_parse_port() only sets port->mediums and port->pairs without populating port->supported. The attach_mdi_port() callbacks for drivers like dp83822 and marvell10g also do not set port->supported before phy_port_update_supported() runs. Does this leave port->supported empty for ports described in device tree? The docstring above this function at line 112 states "Any mode that was manually set in the port's supported list remains set" - but for the DT path where port->supported starts at zero, the AND with zero produces zero regardless of what medium modes were computed. -- pw-bot: cr