diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.15/950-0165-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.15/950-0165-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.15/950-0165-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch b/target/linux/bcm27xx/patches-5.15/950-0165-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch new file mode 100644 index 0000000000..b2f4e6c8c0 --- /dev/null +++ b/target/linux/bcm27xx/patches-5.15/950-0165-net-bcmgenet-Workaround-2-for-Pi4-Ethernet-fail.patch @@ -0,0 +1,51 @@ +From 9af6d93967ff5a2d90a6f82c20f4d6b2785535e7 Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Fri, 9 Aug 2019 08:51:43 +0100 +Subject: [PATCH] net: bcmgenet: Workaround #2 for Pi4 Ethernet fail + +Some combinations of Pi 4Bs and Ethernet switches don't reliably get a +DCHP-assigned IP address, leaving the unit with a self=assigned 169.254 +address. In the failure case, the Pi is left able to receive packets +but not send them, suggesting that the MAC<->PHY link is getting into +a bad state. + +It has been found empirically that skipping a reset step by the genet +driver prevents the failures. No downsides have been discovered yet, +and unlike the forced renegotiation it doesn't increase the time to +get an IP address, so the workaround is enabled by default; add + + genet.skip_umac_reset=n + +to the command line to disable it. + +See: https://github.com/raspberrypi/linux/issues/3108 + +Signed-off-by: Phil Elwell <phil@raspberrypi.org> +--- + drivers/net/ethernet/broadcom/genet/bcmgenet.c | 8 ++++++++ + 1 file changed, 8 insertions(+) + +--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c ++++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c +@@ -67,6 +67,9 @@ + + /* Forward declarations */ + static void bcmgenet_set_rx_mode(struct net_device *dev); ++static bool skip_umac_reset = true; ++module_param(skip_umac_reset, bool, 0444); ++MODULE_PARM_DESC(skip_umac_reset, "Skip UMAC reset step"); + + static inline void bcmgenet_writel(u32 value, void __iomem *offset) + { +@@ -2439,6 +2442,11 @@ static void reset_umac(struct bcmgenet_p + bcmgenet_rbuf_ctrl_set(priv, 0); + udelay(10); + ++ if (skip_umac_reset) { ++ pr_warn("Skipping UMAC reset\n"); ++ return; ++ } ++ + /* issue soft reset and disable MAC while updating its registers */ + bcmgenet_umac_writel(priv, CMD_SW_RESET, UMAC_CMD); + udelay(2); |