From: Stefan Agner <ste...@agner.ch> Sent: Wednesday, April 19, 2017 1:02 PM
>To: Andy Duan <fugang.d...@nxp.com>
>Cc: fugang.d...@freescale.com; feste...@gmail.com;
>netdev@vger.kernel.org; netdev-ow...@vger.kernel.org
>Subject: Re: FEC on i.MX 7 transmit queue timeout
>
>Hi Andy,
>
>On 2017-04-18 19:24, Andy Duan wrote:
>> On 2017年04月19日 03:46, Stefan Agner wrote:
>>> Hi,
>>>
>>> I noticed last week on upstream (v4.11-rc6) on a Colibri iMX7 board
>>> that after a while (~10 minutes) the detdev wachdog prints a
>>> stacktrace and the driver then continuously dumps the TX ring. I then
>>> did a quick test with 4.10, and realized it actually suffers the same
>>> issue, so it seems not to be a regression. I use a rootfs mounted over
>>> NFS...
>>>
>>> ------------[ cut here ]------------
>>> WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:316
>>> dev_watchdog+0x240/0x244
>>> NETDEV WATCHDOG: eth0 (fec): transmit queue 2 timed out Modules
>>> linked in:
>>> CPU: 0 PID: 0 Comm: swapper/0 Not tainted
>>> 4.11.0-rc7-00030-g2c4e6bd0c4f0-dirty #330 Hardware name: Freescale
>>> i.MX7 Dual (Device Tree) [<c02293f0>] (unwind_backtrace) from
>>> [<c0225820>] (show_stack+0x10/0x14) [<c0225820>] (show_stack) from
>>> [<c050db6c>] (dump_stack+0x90/0xa0) [<c050db6c>] (dump_stack) from
>>> [<c023ae68>] (__warn+0xac/0x11c) [<c023ae68>] (__warn) from
>>> [<c023af10>] (warn_slowpath_fmt+0x38/0x48) [<c023af10>]
>>> (warn_slowpath_fmt) from [<c088bb8c>]
>>> (dev_watchdog+0x240/0x244)
>>> [<c088bb8c>] (dev_watchdog) from [<c0294798>]
>>> (run_timer_softirq+0x24c/0x708)
>>> [<c0294798>] (run_timer_softirq) from [<c023f584>]
>>> (__do_softirq+0x12c/0x2a8)
>>> [<c023f584>] (__do_softirq) from [<c023f8c4>] (irq_exit+0xdc/0x13c)
>>> [<c023f8c4>] (irq_exit) from [<c02818ac>]
>>> (__handle_domain_irq+0xa4/0xf8)
>>> [<c02818ac>] (__handle_domain_irq) from [<c0201624>]
>>> (gic_handle_irq+0x34/0xa4)
>>> [<c0201624>] (gic_handle_irq) from [<c0226338>] (__irq_svc+0x58/0x8c)
>>> Exception stack(0xc1201f30 to 0xc1201f78)
>>> 1f20: c0233320 00000000 00000000
>>> 01400000
>>> 1f40: c1203d80 ffffe000 00000000 00000000 c107bf10 c0e055b5 c1203d34
>>> 00000001
>>> 1f60: c07d2324 c1201f80 c0222ac8 c0222acc 60000013 ffffffff
>>> [<c0226338>] (__irq_svc) from [<c0222acc>] (arch_cpu_idle+0x38/0x3c)
>>> [<c0222acc>] (arch_cpu_idle) from [<c0275f24>] (do_idle+0xa8/0x250)
>>> [<c0275f24>] (do_idle) from [<c02760e4>]
>>> (cpu_startup_entry+0x18/0x1c) [<c02760e4>] (cpu_startup_entry) from
>>> [<c1000aa0>]
>>> (start_kernel+0x3fc/0x45c)
>>> ---[ end trace 5b0c6dc3466a7918 ]---
>>> fec 30be0000.ethernet eth0: TX ring dump
>>> Nr SC addr len SKB
>>> 0 0x1c00 0x00000000 590 (null)
>>> 1 0x1c00 0x00000000 590 (null)
>>> 2 0x1c00 0x00000000 42 (null)
>>> 3 H 0x1c00 0x00000000 42 (null)
>>> 4 S 0x0000 0x00000000 0 (null)
>>> 5 0x0000 0x00000000 0 (null)
>>> 6 0x0000 0x00000000 0 (null)
>>> 7 0x0000 0x00000000 0 (null)
>>> 8 0x0000 0x00000000 0 (null)
>>> 9 0x0000 0x00000000 0 (null)
>>> 10 0x0000 0x00000000 0 (null)
>>> 11 0x0000 0x00000000 0 (null)
>>> 12 0x0000 0x00000000 0 (null)
>>> 13 0x0000 0x00000000 0 (null)
>>> 14 0x0000 0x00000000 0 (null)
>>> 15 0x0000 0x00000000 0 (null)
>>> 16 0x0000 0x00000000 0 (null)
>>> 17 0x0000 0x00000000 0 (null)
>>> 18 0x0000 0x00000000 0 (null)
>>> ...
>>>
>>>
>>> A second TX ring dump from 4.10:
>>> fec 30be0000.ethernet eth0: TX ring dump
>>> Nr SC addr len SKB
>>> 0 0x1c00 0x00000000 42 (null)
>>> 1 0x1c00 0x00000000 42 (null)
>>> 2 0x1c00 0x00000000 90 (null)
>>> 3 0x1c00 0x00000000 90 (null)
>>> 4 0x1c00 0x00000000 90 (null)
>>> 5 0x1c00 0x00000000 218 (null)
>>> 6 0x1c00 0x00000000 218 (null)
>>> 7 0x1c00 0x00000000 218 (null)
>>> 8 0x1c00 0x00000000 90 (null)
>>> 9 0x1c00 0x00000000 206 (null)
>>> 10 0x1c00 0x00000000 216 (null)
>>> 11 0x1c00 0x00000000 216 (null)
>>> 12 0x1c00 0x00000000 216 (null)
>>> 13 0x1c00 0x00000000 311 (null)
>>> 14 0x1c00 0x00000000 178 (null)
>>> 15 0x1c00 0x00000000 311 (null)
>>> 16 0x1c00 0x00000000 206 (null)
>>> 17 H 0x1c00 0x00000000 311 (null)
>>> 18 S 0x0000 0x00000000 0 (null)
>>> 19 0x0000 0x00000000 0 (null)
>> The dump show tx ring is fine.
>>
>>>
>>> The ring dump prints continously, but I can access console every now
>>> and then. I noticed that the second interrupt seems static (66441, TX
>>> interrupt?):
>>> 58: 18 GIC-0 150 Level 30be0000.ethernet
>>> 59: 66441 GIC-0 151 Level 30be0000.ethernet
>>> 60: 70477 GIC-0 152 Level 30be0000.ethernet
>> 150 irq number is for tx/rx queue 1 receive/transmit buffer/frame done.
>> 151 irq number is for tx/rx queue 2 receive/transmit buffer/frame done.
>> 152 irq number is for tx/rx queue 0 receive/transmit buffer/frame
>> done, mii interrupt and others.
>>
>> i.MX7D enet has three queues for tx and rx.
>> It seems netdev pick tx queue 1 rate is very rare by __netdev_pick_tx().
>
>Oh ok I see, and it seems to choose queue 2 fairly often...
>
>>> Anybody else seen this? Any idea?
>>>
>>> In 4.10 as well as 4.11-rc6 the interrupt counts were just over 65536...
>>> pure chance?
>>>
>>>
>> you can use ethtool to set the irq coalesce like:
>> ethtool -c eth0 rx-frames 80
>> ethtool -c eth0 rx-usecs 600
>> ethtool -c eth0 tx-frames 64
>> ethtool -c eth0 tx-usenc 700
>>
>>
>> You don't run any test case, just nfs mount rootfs ?
>> I will setup one imx7d sdb board to run it.
>
>I noticed it without doing anything, just boot via NFS. There was always a
>little
>bit of activity, at least according to the link (blinks every ~5s).
>
>It seemd that it happened a bit earlier when using iperf to exacerbate the
>problem...
>
>I noticed that errata 7885 is not mentioned in the i.MX 7 errata, so I created
>a
>new devtype:
>
> }, {
> .name = "imx7d-fec",
> .driver_data = FEC_QUIRK_ENET_MAC | FEC_QUIRK_HAS_GBIT |
> FEC_QUIRK_HAS_BUFDESC_EX | FEC_QUIRK_HAS_CSUM |
> FEC_QUIRK_HAS_VLAN | FEC_QUIRK_BUG_CAPTURE |
> FEC_QUIRK_HAS_RACC | FEC_QUIRK_HAS_COALESCE,
> }, {
>
Upstreaming driver doesn't have the platform_device_id for "imx7d-fec", imx7d
enet still use imx6sx-fec device id driver.
It lost FEC_QUIRK_ERR007885 and FEC_QUIRK_HAS_AVB quirk flags.
You can add these.
I validate imx7d sdb board with 4.11.0-rc6, no such problem after nfs mount
more than 3.5 hours.
>I had that running for about 6h with iperf, it did not seem to happen despite
>lots of traffic and interrupts:
> 58: 12782877 GIC-0 150 Level 30be0000.ethernet
> 59: 14607039 GIC-0 151 Level 30be0000.ethernet
> 60: 32356307 GIC-0 152 Level 30be0000.ethernet
>
>But just when I restarted the same stack trace appeared again....
>
>--
>Stefan
