Jesper Dangaard Brouer says:
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Fix qdisc noop issue caused by driver and identify future bugs
I've been very puzzled why networking on my NXP development board,
using driver dpaa2-eth, stopped working when I updated the kernel
version >= 5.3. The observable issue were that interface would drop
all TX packets, because it had assigned the qdisc noop.
This turned out the be a NIC driver bug, that would only get triggered
when using sysctl net/core/default_qdisc=fq_codel. It was non-trivial
to find out[1] this was driver related. Thus, this patchset besides
fixing the driver bug, also helps end-user identify the issue.
[1]: https://github.com/xdp-project/xdp-project/blob/master/areas/arm64/board_nxp_ls1088/nxp-board04-troubleshoot-qdisc.org
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Signed-off-by: David S. Miller <davem@davemloft.net>