Date: Tue, 31 Jul 2018 15:45:50 +0200 From: Gergely Kiss <mail.gery@gmail.com> To: freebsd-mips@freebsd.org Subject: Possible arge driver bug - interrupt storm on int2 Message-ID: <CAF-mK=XgWWjF3rU4f6s_6bb8bzYfmNjNnwwqmShM9yWX_sLzPQ@mail.gmail.com>
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Hi, I'm working on improving the freebsd-wifi-build project to have an out-of-the-box gateway solution built on FreeBSD for SOHO routers. For more information, please see below link: https://github.com/kissg1988/freebsd-wifi-build I've created a build script that should simplify creating a build environment from scratch: https://github.com/kissg1988/freebsd-wifi-build/blob/buildscript/scripts/build.sh The goal is to make the distribution easy to build and use so it can be flashed just as simple as OpenWrt or DD-WRT. The device I'm working with is a TP-Link WN-1043ND v1.8 which has a Realtek RTL8366RB switch and is built around the AR9132 SoC. The board runs 11.2-RELEASE currently. The ethernet controller works perfectly with a static or DHCP provided IP address, however it seems something is wrong with the way the driver handles the TX queue in case 802.1Q tagging is in use and the system tries sending PPP frames over the tagged interface (eg. vlan2). Once ppp starts establishing the connection, packets to be sent are queued but not being transmitted by the controller and an interrupt storm is generated with only the TX_UNDERRUN flag set (without the TX_PKT_SENT flag). This might be related to an issue seen a few years back: https://lists.freebsd.org/pipermail/freebsd-mips/2015-October/004137.html As PPPoE has an 8-byte overhead and VLAN tagging needs an additional 4-byte field, I have lowered the MTU on arge0 and vlan2 to 1488 bytes but it didn't make any difference, the interrupt storm still happens and it's always reproducible. Once it starts, the only way to stop the storm is to bring down arge0. If I destroy the vlan interface, and put the WAN port to an access VLAN with no tagging, the PPPoE connection works fine. I'll make some more tests later today with -HEAD to see if it makes any difference. Any help or ideas would be much appreciated in the meantime. Thanks, Gergely
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