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SubjectRe: [RFC] net: phy: read link status twice when phy_check_link_status()
From
Date
:/sys/kernel/debug/tracing$ cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 45/45 #P:128
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
kworker/64:2-1028 [064] .... 172.295687: mdio_access: mii-0000:bd:00.0 read phy:0x01 reg:0x02 val:0x001c
kworker/64:2-1028 [064] .... 172.295726: mdio_access: mii-0000:bd:00.0 read phy:0x01 reg:0x03 val:0xc916
kworker/64:2-1028 [064] .... 172.296902: mdio_access: mii-0000:bd:00.0 read phy:0x01 reg:0x01 val:0x79ad
kworker/64:2-1028 [064] .... 172.296938: mdio_access: mii-0000:bd:00.0 read phy:0x01 reg:0x0f val:0x2000
kworker/64:2-1028 [064] .... 172.321213: mdio_access: mii-0000:bd:00.0 read phy:0x01 reg:0x00 val:0x1040
kworker/64:2-1028 [064] .... 172.343209: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x02 val:0x001c
kworker/64:2-1028 [064] .... 172.343245: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x03 val:0xc916
kworker/64:2-1028 [064] .... 172.343882: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79ad
kworker/64:2-1028 [064] .... 172.343918: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x0f val:0x2000
kworker/64:2-1028 [064] .... 172.362658: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x00 val:0x1040
kworker/64:2-1028 [064] .... 172.385961: mdio_access: mii-0000:bd:00.2 read phy:0x05 reg:0x02 val:0x001c
kworker/64:2-1028 [064] .... 172.385996: mdio_access: mii-0000:bd:00.2 read phy:0x05 reg:0x03 val:0xc916
kworker/64:2-1028 [064] .... 172.386646: mdio_access: mii-0000:bd:00.2 read phy:0x05 reg:0x01 val:0x79ad
kworker/64:2-1028 [064] .... 172.386681: mdio_access: mii-0000:bd:00.2 read phy:0x05 reg:0x0f val:0x2000
kworker/64:2-1028 [064] .... 172.411286: mdio_access: mii-0000:bd:00.2 read phy:0x05 reg:0x00 val:0x1040
kworker/64:2-1028 [064] .... 172.433225: mdio_access: mii-0000:bd:00.3 read phy:0x07 reg:0x02 val:0x001c
kworker/64:2-1028 [064] .... 172.433260: mdio_access: mii-0000:bd:00.3 read phy:0x07 reg:0x03 val:0xc916
kworker/64:2-1028 [064] .... 172.433887: mdio_access: mii-0000:bd:00.3 read phy:0x07 reg:0x01 val:0x79ad
kworker/64:2-1028 [064] .... 172.433922: mdio_access: mii-0000:bd:00.3 read phy:0x07 reg:0x0f val:0x2000
kworker/64:2-1028 [064] .... 172.452862: mdio_access: mii-0000:bd:00.3 read phy:0x07 reg:0x00 val:0x1040
ifconfig-1324 [011] .... 177.325585: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x00 val:0x1040
kworker/u257:0-8 [012] .... 177.325642: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x04 val:0x01e1
kworker/u257:0-8 [012] .... 177.325654: mdio_access: mii-0000:bd:00.1 write phy:0x03 reg:0x04 val:0x05e1
kworker/u257:0-8 [012] .... 177.325708: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79ad
kworker/u257:0-8 [012] .... 177.325744: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x09 val:0x0200
kworker/u257:0-8 [012] .... 177.325779: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x00 val:0x1040
kworker/u257:0-8 [012] .... 177.325788: mdio_access: mii-0000:bd:00.1 write phy:0x03 reg:0x00 val:0x1240
kworker/u257:0-8 [012] .... 177.325843: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x798d
kworker/u257:0-8 [003] .... 178.360488: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x7989
kworker/u257:0-8 [000] .... 179.384479: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x7989
kworker/u257:0-8 [000] .... 180.408477: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x7989
kworker/u257:0-8 [000] .... 181.432474: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79a9
kworker/u257:0-8 [000] .... 181.432510: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x0a val:0x7800
kworker/u257:0-8 [000] .... 181.432546: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x09 val:0x0200
kworker/u257:0-8 [000] .... 181.432582: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x05 val:0xc1e1
kworker/u257:0-8 [000] .... 182.456510: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79ad
kworker/u257:0-8 [000] .... 182.456546: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x0a val:0x4800
kworker/u257:0-8 [000] .... 182.456582: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x09 val:0x0200
kworker/u257:0-8 [000] .... 182.456618: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x05 val:0xc1e1
kworker/u257:0-8 [001] .... 183.480476: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79ad
kworker/u257:0-8 [000] .... 184.504478: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79ad
kworker/u257:0-8 [000] .... 185.528486: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79ad
kworker/u257:0-8 [000] .... 186.552475: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x01 val:0x79ad
ifconfig-1327 [011] .... 187.196036: mdio_access: mii-0000:bd:00.1 read phy:0x03 reg:0x00 val:0x1040
ifconfig-1327 [011] .... 187.196046: mdio_access: mii-0000:bd:00.1 write phy:0x03 reg:0x00 val:0x1840



On 2019/7/30 14:08, Heiner Kallweit wrote:
> On 30.07.2019 06:03, liuyonglong wrote:
>>
>>
>> On 2019/7/30 4:57, Heiner Kallweit wrote:
>>> On 29.07.2019 05:59, liuyonglong wrote:
>>>>
>>>>
>>>> On 2019/7/27 2:14, Heiner Kallweit wrote:
>>>>> On 26.07.2019 11:53, Yonglong Liu wrote:
>>>>>> According to the datasheet of Marvell phy and Realtek phy, the
>>>>>> copper link status should read twice, or it may get a fake link
>>>>>> up status, and cause up->down->up at the first time when link up.
>>>>>> This happens more oftem at Realtek phy.
>>>>>>
>>>>> This is not correct, there is no fake link up status.
>>>>> Read the comment in genphy_update_link, only link-down events
>>>>> are latched. Means if the first read returns link up, then there
>>>>> is no need for a second read. And in polling mode we don't do a
>>>>> second read because we want to detect also short link drops.
>>>>>
>>>>> It would be helpful if you could describe your actual problem
>>>>> and whether you use polling or interrupt mode.
>>>>>
>>>>
>>>> [ 44.498633] hns3 0000:bd:00.1 eth5: net open
>>>> [ 44.504273] hns3 0000:bd:00.1: reg=0x1, data=0x79ad -> called from phy_start_aneg
>>>> [ 44.532348] hns3 0000:bd:00.1: reg=0x1, data=0x798d -> called from phy_state_machine,update link.
>>>
>>> This should not happen. The PHY indicates link up w/o having aneg finished.
>>>
>>>>
>>>> According to the datasheet:
>>>> reg 1.5=0 now, means copper auto-negotiation not complete
>>>> reg 1.2=1 now, means link is up
>>>>
>>>> We can see that, when we read the link up, the auto-negotiation
>>>> is not complete yet, so the speed is invalid.
>>>>
>>>> I don't know why this happen, maybe this state is keep from bios?
>>>> Or we may do something else in the phy initialize to fix it?
>>>> And also confuse that why read twice can fix it?
>>>>
>>> I suppose that basically any delay would do.
>>>
>>>> [ 44.554063] hns3 0000:bd:00.1: invalid speed (-1)
>>>> [ 44.560412] hns3 0000:bd:00.1 eth5: failed to adjust link.
>>>> [ 45.194870] hns3 0000:bd:00.1 eth5: link up
>>>> [ 45.574095] hns3 0000:bd:00.1: phyid=3, reg=0x1, data=0x7989
>>>> [ 46.150051] hns3 0000:bd:00.1 eth5: link down
>>>> [ 46.598074] hns3 0000:bd:00.1: phyid=3, reg=0x1, data=0x7989
>>>> [ 47.622075] hns3 0000:bd:00.1: phyid=3, reg=0x1, data=0x79a9
>>>> [ 48.646077] hns3 0000:bd:00.1: phyid=3, reg=0x1, data=0x79ad
>>>> [ 48.934050] hns3 0000:bd:00.1 eth5: link up
>>>> [ 49.702140] hns3 0000:bd:00.1: phyid=3, reg=0x1, data=0x79ad
>>>>
>>>>>> I add a fake status read, and can solve this problem.
>>>>>>
>>>>>> I also see that in genphy_update_link(), had delete the fake
>>>>>> read in polling mode, so I don't know whether my solution is
>>>>>> correct.
>>>>>>
>>>
>>> Can you test whether the following fixes the issue for you?
>>> Also it would be interesting which exact PHY models you tested
>>> and whether you built the respective PHY drivers or whether you
>>> rely on the genphy driver. Best use the second patch to get the
>>> needed info. It may make sense anyway to add the call to
>>> phy_attached_info() to the hns3 driver.
>>>
>>
>> [ 40.100716] RTL8211F Gigabit Ethernet mii-0000:bd:00.3:07: attached PHY driver [RTL8211F Gigabit Ethernet] (mii_bus:phy_addr=mii-0000:bd:00.3:07, irq=POLL)
>> [ 40.932133] hns3 0000:bd:00.3 eth7: net open
>> [ 40.932458] hns3 0000:bd:00.3: invalid speed (-1)
>> [ 40.932541] 8021q: adding VLAN 0 to HW filter on device eth7
>> [ 40.937149] hns3 0000:bd:00.3 eth7: failed to adjust link.
>>
>> [ 40.662050] Generic PHY mii-0000:bd:00.2:05: attached PHY driver [Generic PHY] (mii_bus:phy_addr=mii-0000:bd:00.2:05, irq=POLL)
>> [ 41.563511] hns3 0000:bd:00.2 eth6: net open
>> [ 41.563853] hns3 0000:bd:00.2: invalid speed (-1)
>> [ 41.563943] 8021q: adding VLAN 0 to HW filter on device eth6
>> [ 41.568578] IPv6: ADDRCONF(NETDEV_CHANGE): eth6: link becomes ready
>> [ 41.568898] hns3 0000:bd:00.2 eth6: failed to adjust link.
>>
>> I am using RTL8211F, but you can see that, both genphy driver and
>> RTL8211F driver have the same issue.
>>
>>>
>>> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
>>> index 6b5cb87f3..fbecfe210 100644
>>> --- a/drivers/net/phy/phy_device.c
>>> +++ b/drivers/net/phy/phy_device.c
>>> @@ -1807,7 +1807,8 @@ int genphy_read_status(struct phy_device *phydev)
>>>
>>> linkmode_zero(phydev->lp_advertising);
>>>
>>> - if (phydev->autoneg == AUTONEG_ENABLE && phydev->autoneg_complete) {
>>> + if (phydev->autoneg == AUTONEG_ENABLE &&
>>> + (phydev->autoneg_complete || phydev->link)) {
>>> if (phydev->is_gigabit_capable) {
>>> lpagb = phy_read(phydev, MII_STAT1000);
>>> if (lpagb < 0)
>>>
>>
>> I have try this patch, have no effect. I suppose that at this time,
>> the autoneg actually not complete yet.
>>
>> Maybe the wrong phy state is passed from bios? Invalid speed just
>> happen at the first time when ethX up, after that, repeat the
>> ifconfig down/ifconfig up command can not see that again.
>>
>> So I think the bios should power off the phy(writing reg 1.11 to 1)
>> before it starts the OS? Or any other way to fix this in the OS?
>>
> To get a better idea of whats going on it would be good to see a full
> MDIO trace. Can you enable MDIO tracing via the following sysctl file
> /sys/kernel/debug/tracing/events/mdio/enable
> and provide the generated trace?
>
> Due to polling mode each second entries will be generated, so you
> better stop network after the issue occurred.
>
>>
>>
>>
>
> Heiner
>
> .
>

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