From: Richard Leitner <richard.leitner@xxxxxxxxxxx> From: Richard Leitner <richard.leitner@xxxxxxxxxxx> Some PHYs (for example the LAN8710) doesn't allow turning the ethernet ref clocks off and on again without reset (according to their datasheet). Exactly this behaviour was introduced for power saving reasons by commit e8fcfcd5684a ("net: fec: optimize the clock management to save...") Therefore remove those en/disables of the refclk during probe, open and close of the fec. Generally speaking is this issue only be relevant if the ref clk for the PHY is generated by the SoC. In our specific case (PCB) this problem does occur at about every 10th to 50th POR of an LAN8710 connected to an i.MX6 SoC. The typical symptom of this problem is a "swinging" ethernet link. Similar issues were experienced by users of the NXP forum: https://community.nxp.com/thread/389902 https://community.nxp.com/message/309354 With this patch applied the issue didn't occur for at least a few thousand PORs of our board. Fixes: e8fcfcd5684a ("net: fec: optimize the clock management to sa...") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Richard Leitner <richard.leitner@xxxxxxxxxxx> --- drivers/net/ethernet/freescale/fec_main.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 3dc2d771a222..8f696b53d8b8 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -2844,9 +2844,6 @@ fec_enet_open(struct net_device *ndev) return ret; pinctrl_pm_select_default_state(&fep->pdev->dev); - ret = fec_enet_clk_enable(ndev, true); - if (ret) - goto clk_enable; /* I should reset the ring buffers here, but I don't yet know * a simple way to do that. @@ -2879,8 +2876,6 @@ fec_enet_open(struct net_device *ndev) err_enet_mii_probe: fec_enet_free_buffers(ndev); err_enet_alloc: - fec_enet_clk_enable(ndev, false); -clk_enable: pm_runtime_mark_last_busy(&fep->pdev->dev); pm_runtime_put_autosuspend(&fep->pdev->dev); pinctrl_pm_select_sleep_state(&fep->pdev->dev); @@ -2907,7 +2902,6 @@ fec_enet_close(struct net_device *ndev) fec_enet_update_ethtool_stats(ndev); - fec_enet_clk_enable(ndev, false); pinctrl_pm_select_sleep_state(&fep->pdev->dev); pm_runtime_mark_last_busy(&fep->pdev->dev); pm_runtime_put_autosuspend(&fep->pdev->dev); @@ -3495,7 +3489,6 @@ fec_probe(struct platform_device *pdev) /* Carrier starts down, phylib will bring it up */ netif_carrier_off(ndev); - fec_enet_clk_enable(ndev, false); pinctrl_pm_select_sleep_state(&pdev->dev); ret = register_netdev(ndev); -- 2.11.0