From: Krzysztof Hałasa khalasa@piap.pl
[ Upstream commit 4145f00227ee80f21ab274e9cd9c09758e9bcf3d ]
ASIX AX88772B based USB 10/100 Ethernet adapter doesn't come up ("carrier off"), despite the built-in 100BASE-FX PHY positive link indication. The internal PHY is configured (using EEPROM) in fixed 100 Mbps full duplex mode.
The primary problem appears to be using carrier_netif_{on,off}() while, at the same time, delegating carrier management to phylink. Use only the latter and remove "manual control" in the asix driver.
I don't have any other AX88772 board here, but the problem doesn't seem specific to a particular board or settings - it's probably timing-dependent.
Remove unused asix_adjust_link() as well.
Signed-off-by: Krzysztof Hałasa khalasa@piap.pl Tested-by: Oleksij Rempel o.rempel@pengutronix.de Link: https://patch.msgid.link/m3plhmdfte.fsf_-_@t19.piap.pl Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org ---
**YES** This commit should be backported to stable kernel trees. Here's my detailed analysis: ## Why This Should Be Backported ### 1. **Clear Bug Fix Nature** This commit fixes a functional bug where ASIX AX88772B USB Ethernet adapters fail to establish carrier state ("carrier off") despite the PHY indicating a positive link. This is a real-world connectivity issue that affects users' ability to use their network hardware. ### 2. **Code Analysis - Specific Changes** Looking at the diff, the changes are: - **Removed `asix_adjust_link()` function** from `asix_common.c` - This function was manually calling `usbnet_link_change()` which conflicts with phylink - **Removed `usbnet_link_change()` calls** from `ax88772_mac_link_up()` and `ax88772_mac_link_down()` in `asix_devices.c` - **Removed `.status = asix_status`** from driver info structures for AX88772 devices - **Removed `FLAG_LINK_INTR`** from AX88772 device driver flags These changes eliminate the dual carrier control conflict by removing manual carrier management and letting phylink handle it exclusively. ### 3. **Low Risk Profile** - **Removes conflicting code** rather than adding new functionality - **Small, focused changes** that address a specific technical conflict - **Phylink is well-established** and already properly handles carrier management for these devices - **Changes are targeted** to specific hardware (AX88772) rather than broad architectural changes ### 4. **Comparison to Similar "NO" Commits** The provided similar commits were marked "NO" because they were: - **Feature additions** (phylink migration, selftest support) - **Architectural changes** (migrating from MII to phylink) - **Enhancements** rather than bug fixes This commit is fundamentally different - it's a **bug fix** that resolves a conflict introduced by previous phylink migration work. ### 5. **User Impact** This affects users who have ASIX AX88772B adapters that don't work properly due to carrier detection issues. This is likely a regression from earlier phylink migration commits, making it a critical fix for hardware compatibility. ### 6. **Stable Tree Criteria Compliance** - ✅ **Important bug fix** - Fixes network connectivity issues - ✅ **Minimal risk** - Removes conflicting code, doesn't introduce new features - ✅ **Small and contained** - Changes are focused on carrier control conflict - ✅ **No architectural changes** - Simplifies by removing duplicate functionality - ✅ **Clear side effects** - Only affects AX88772 devices, improves their functionality The commit message explicitly states this fixes a timing-dependent issue where devices "don't come up" despite proper PHY indication, which is exactly the type of hardware compatibility bug that stable trees aim to address.
drivers/net/usb/asix.h | 1 - drivers/net/usb/asix_common.c | 22 ---------------------- drivers/net/usb/asix_devices.c | 17 ++++------------- 3 files changed, 4 insertions(+), 36 deletions(-)
diff --git a/drivers/net/usb/asix.h b/drivers/net/usb/asix.h index 74162190bccc1..8531b804021aa 100644 --- a/drivers/net/usb/asix.h +++ b/drivers/net/usb/asix.h @@ -224,7 +224,6 @@ int asix_write_rx_ctl(struct usbnet *dev, u16 mode, int in_pm);
u16 asix_read_medium_status(struct usbnet *dev, int in_pm); int asix_write_medium_mode(struct usbnet *dev, u16 mode, int in_pm); -void asix_adjust_link(struct net_device *netdev);
int asix_write_gpio(struct usbnet *dev, u16 value, int sleep, int in_pm);
diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c index 72ffc89b477ad..7fd763917ae2c 100644 --- a/drivers/net/usb/asix_common.c +++ b/drivers/net/usb/asix_common.c @@ -414,28 +414,6 @@ int asix_write_medium_mode(struct usbnet *dev, u16 mode, int in_pm) return ret; }
-/* set MAC link settings according to information from phylib */ -void asix_adjust_link(struct net_device *netdev) -{ - struct phy_device *phydev = netdev->phydev; - struct usbnet *dev = netdev_priv(netdev); - u16 mode = 0; - - if (phydev->link) { - mode = AX88772_MEDIUM_DEFAULT; - - if (phydev->duplex == DUPLEX_HALF) - mode &= ~AX_MEDIUM_FD; - - if (phydev->speed != SPEED_100) - mode &= ~AX_MEDIUM_PS; - } - - asix_write_medium_mode(dev, mode, 0); - phy_print_status(phydev); - usbnet_link_change(dev, phydev->link, 0); -} - int asix_write_gpio(struct usbnet *dev, u16 value, int sleep, int in_pm) { int ret; diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c index da24941a6e444..9b0318fb50b55 100644 --- a/drivers/net/usb/asix_devices.c +++ b/drivers/net/usb/asix_devices.c @@ -752,7 +752,6 @@ static void ax88772_mac_link_down(struct phylink_config *config, struct usbnet *dev = netdev_priv(to_net_dev(config->dev));
asix_write_medium_mode(dev, 0, 0); - usbnet_link_change(dev, false, false); }
static void ax88772_mac_link_up(struct phylink_config *config, @@ -783,7 +782,6 @@ static void ax88772_mac_link_up(struct phylink_config *config, m |= AX_MEDIUM_RFC;
asix_write_medium_mode(dev, m, 0); - usbnet_link_change(dev, true, false); }
static const struct phylink_mac_ops ax88772_phylink_mac_ops = { @@ -1350,10 +1348,9 @@ static const struct driver_info ax88772_info = { .description = "ASIX AX88772 USB 2.0 Ethernet", .bind = ax88772_bind, .unbind = ax88772_unbind, - .status = asix_status, .reset = ax88772_reset, .stop = ax88772_stop, - .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_LINK_INTR | FLAG_MULTI_PACKET, + .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_MULTI_PACKET, .rx_fixup = asix_rx_fixup_common, .tx_fixup = asix_tx_fixup, }; @@ -1362,11 +1359,9 @@ static const struct driver_info ax88772b_info = { .description = "ASIX AX88772B USB 2.0 Ethernet", .bind = ax88772_bind, .unbind = ax88772_unbind, - .status = asix_status, .reset = ax88772_reset, .stop = ax88772_stop, - .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_LINK_INTR | - FLAG_MULTI_PACKET, + .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_MULTI_PACKET, .rx_fixup = asix_rx_fixup_common, .tx_fixup = asix_tx_fixup, .data = FLAG_EEPROM_MAC, @@ -1376,11 +1371,9 @@ static const struct driver_info lxausb_t1l_info = { .description = "Linux Automation GmbH USB 10Base-T1L", .bind = ax88772_bind, .unbind = ax88772_unbind, - .status = asix_status, .reset = ax88772_reset, .stop = ax88772_stop, - .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_LINK_INTR | - FLAG_MULTI_PACKET, + .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_MULTI_PACKET, .rx_fixup = asix_rx_fixup_common, .tx_fixup = asix_tx_fixup, .data = FLAG_EEPROM_MAC, @@ -1412,10 +1405,8 @@ static const struct driver_info hg20f9_info = { .description = "HG20F9 USB 2.0 Ethernet", .bind = ax88772_bind, .unbind = ax88772_unbind, - .status = asix_status, .reset = ax88772_reset, - .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_LINK_INTR | - FLAG_MULTI_PACKET, + .flags = FLAG_ETHER | FLAG_FRAMING_AX | FLAG_MULTI_PACKET, .rx_fixup = asix_rx_fixup_common, .tx_fixup = asix_tx_fixup, .data = FLAG_EEPROM_MAC,