Re: 2.6.20-rc7: known regressions (v2) (part 1)

[Adam Kropelin]

Auke Kok wrote:
> Adam Kropelin wrote:
> > I've never had this device work 100% with MSI on any kernel version
> > I've tested so far. But I'm not the original reporter of the
> > problem, and I believe for him it was a true regression where a
> > previous kernel wored correctly.
>
> maybe I've been unclear, but here's how e1000 detects link changes:
>
> 1) by checking every 2 seconds in the watchdog by reading PHY
> registers

That would explain why I see link status changes but 0 interrupt count 
in /proc/interrupts. However, on >= 2.6.19 the link state never changes. 
Ever. It's always down. On <= 2.6.18 the link state does change but with 
0 interupt count.

> 2) by receiving an interrupt from the NIC with the LSI bit
> in the interrupt control register
>
> if the link is down to start with, the watchdog will obviously spot a
> 'link up' change since it doesn't use any interrupts.

This does not seem to work on 2.6.19+. Unless the watchdog interval is 
tens of minutes. I've waited at least 5 minutes and link never went up.

> > The behavior I observe on 2.6.19 is better than 2.6.20-rc7. Link
> > status interrupts seem to work but rx/tx does not. A few more
> > details here:
> <http://www.kroptech.com/~adk0212/mailimport/showmsg.php?msg_id=3339092450&db_name=linux_kernel>
>
> > I'm going to test 2.6.16 thru 2.6.20-rc7 this weekend and will report
> > back any variations in behavior I notice.
>
> that would be a good start, but I still think that you might have a
> broken bridge on that system. Anyway, thanks for digging into this.

Will continue to dig.

--Adam

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