phy_check_downshift(9)

okay so bestie, welcome to phy_check_downshift(9) — that’s the Kernel API Manual page we’re reading, and it’s honestly a whole little vibe check for your PHY. 💅✨

🌸 NAME 🌸

phy_check_downshift — check whether downshift occurred. Periodt. 💖

🦋 SYNOPSIS 🦋

void phy_check_downshift (struct phy_device *phydev );

No cap, that’s the whole signature. 🫶

🎀 ARGUMENTS 🎀

• phydev — the phy_device struct. Yep, the struct phy_device itself is what you pass in, bestie. 💖

✨ DESCRIPTION ✨

So this function checks whether a downshift to a lower speed occurred. If that should be the case, it warns the user. 🚨

The prerequisite for detecting downshift is that the PHY driver implements the read_status callback and sets phydev->speed to the actual link speed. That’s the prerequisite, periodt. 🫶

🌈 SEE ALSO 🌈

Kernel file: ./drivers/net/phy/phy-core.c. Here’s the full lineup, and yes every single one is invited to the group chat: 💅

• phy_speed_to_str(9)
• phy_duplex_to_str(9)
• phy_rate_matching_to_str(9)
• phy_fix_phy_mode_for_mac_delays(9)
• phy_interface_num_ports(9)
• phy_set_max_speed(9)
• of_set_phy_timing_role(9)
• phy_resolve_aneg_pause(9)
• phy_resolve_aneg_linkmode(9)
• __phy_read_mmd(9)
• phy_read_mmd(9)
• __phy_write_mmd(9)
• phy_write_mmd(9)
• phy_modify_changed(9)
• __phy_modify(9)
• phy_modify(9)
• __phy_modify_mmd_changed(9)
• phy_modify_mmd_changed(9)
• __phy_modify_mmd(9)
• phy_modify_mmd(9)
• phy_save_page(9)
• phy_select_page(9)
• phy_restore_page(9)
• phy_read_paged(9)
• phy_write_paged(9)
• phy_modify_paged_changed(9)
• phy_modify_paged(9)

And that’s the whole page, bestie. Footer tea for the record: this one lives under ./drivers/net/phy, the date on it is October 2026, and it’s still phy_check_downshift(9). Slay. 💖🎀