On 31.07.2019 05:33, liuyonglong wrote: > > > On 2019/7/31 3:04, Heiner Kallweit wrote: >> On 30.07.2019 08:35, liuyonglong wrote: >>> :/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 >> >> What I think that happens here: >> Writing 0x1240 to BMCR starts aneg. When reading BMSR immediately after that >> then the PHY seems to have cleared >> the "aneg complete" bit already, but not yet the "link up" bit. This results >> in the false "link up" notification. >> The following patch is based on the fact that in case of enabled aneg we >> can't have a valid link if aneg isn't >> finished. Could you please test whether this works for you? >> >> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c >> index 6b5cb87f3..7ddd91df9 100644 >> --- a/drivers/net/phy/phy_device.c >> +++ b/drivers/net/phy/phy_device.c >> @@ -1774,6 +1774,12 @@ int genphy_update_link(struct phy_device *phydev) >> phydev->link = status & BMSR_LSTATUS ? 1 : 0; >> phydev->autoneg_complete = status & BMSR_ANEGCOMPLETE ? 1 : 0; >> >> + /* Consider the case that autoneg was started and "aneg complete" >> + * bit has been reset, but "link up" bit not yet. >> + */ >> + if (phydev->autoneg == AUTONEG_ENABLE && !phydev->autoneg_complete) >> + phydev->link = 0; >> + >> return 0; >> } >> EXPORT_SYMBOL(genphy_update_link); >> > > This patch can solve the issue! Will it be upstream? > I'll check for side effects, but in general: yes.
> So it's nothing to do with the bios, and just the PHY's own behavior, > the "link up" bit can not reset immediately，right? > Yes, it's the PHY's own behavior, and to a certain extent it may depend on speed of the MDIO bus. At least few network chips require a delay of several microseconds after each MDIO bus access. This may be sufficient for the PHY to reset the link-up bit in time. > ps: It will take 1 second more to make the link up for RTL8211F when 0x798d > happend. > In polling mode link-up is detected up to 1s after it happened. You could switch to interrupt mode to reduce the aneg time. > > Heiner
