Re: [PATCH net] net: dsa: lantiq_gswip: fix maximum frame length
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: 2021-09-01 21:31:02
Also in:
stable
On 9/1/21 8:49 PM, Jan Hoffmann wrote:
Currently, outgoing packets larger than 1496 bytes are dropped when tagged VLAN is used on a switch port. Add the frame check sequence length to the value of the register GSWIP_MAC_FLEN to fix this. This matches the lantiq_ppa vendor driver, which uses a value consisting of 1518 bytes for the MAC frame, plus the lengths of special tag and VLAN tags.
This field is the size of the Ethernet Frame which probably includes the FCS which your patch adds. There is also a discussion in the OpenWrt github about the same topic: https://github.com/openwrt/openwrt/pull/4353
Fixes: 14fceff4771e ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Cc: stable@vger.kernel.org
Signed-off-by: Jan Hoffmann <redacted>Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
quoted hunk ↗ jump to hunk
--- drivers/net/dsa/lantiq_gswip.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c index e78026ef6d8c..64d6dfa83122 100644 --- a/drivers/net/dsa/lantiq_gswip.c +++ b/drivers/net/dsa/lantiq_gswip.c@@ -843,7 +843,8 @@ static int gswip_setup(struct dsa_switch *ds) gswip_switch_mask(priv, 0, GSWIP_MAC_CTRL_2_MLEN, GSWIP_MAC_CTRL_2p(cpu_port)); - gswip_switch_w(priv, VLAN_ETH_FRAME_LEN + 8, GSWIP_MAC_FLEN); + gswip_switch_w(priv, VLAN_ETH_FRAME_LEN + 8 + ETH_FCS_LEN, + GSWIP_MAC_FLEN); gswip_switch_mask(priv, 0, GSWIP_BM_QUEUE_GCTRL_GL_MOD, GSWIP_BM_QUEUE_GCTRL);
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