Messages in this thread | | | Date | Thu, 03 Apr 2014 09:17:29 +0200 | From | Alexander Holler <> | Subject | Re: [PATCH regression] net: phy: fix initialization (config_init) for Marvel 88E1116R PHYs |
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Am 03.04.2014 00:27, schrieb Sebastian Hesselbarth: > On 04/03/2014 12:12 AM, Alexander Holler wrote:
>>> I am curious, how you determined above commit to be the cause of the >>> regression you are seeing. Can you bisect, if you didn't already? >> >> There was no bisecting necessary. I've just looked at what changed in >> mv643xx_eth since 3.13 and the first commit I've reverted was already a >> hit. Reading a bit source revealed the differences between the old reset >> and the newly used one and ended up with my patch (first try) and was a >> hit too. > > Honestly, your own fix changes a different driver than mv643xx_eth.
It changes stuff which now (through the mentioned commit) gets used through the change in mv643xx_eth.
> There is a lot of changes from v3.13 to v3.14 and bisecting really > helps to pin-point the one offending patch. As you can see from my > tests with Dockstar, poking in the PHY driver may not be the right > place to fix it. > >> Actually I assumed the reset needs longer than the 500ms, but as the >> printks revealed, the reset is much faster. >> So the problem seems to be the much increased time (1s) the newly used >> reset function idles in mdelay. > > You assume that the PHY issue comes from waiting for too long _after_ > the reset? And again, the very same PHY on Dockstar is not affected.
Guess with which hardware I'm experiencing this problem? Hint: http://ahsoftware.de/dockstar/ ;)
> >> But I think I have found the real reason. and the change of the reset >> just increased the chance the problem is hit (here with 100% success or >> fail rate however you want to name it). >> >> Just give me a day or two to find the time to verify my assumption (I >> don't want to speculate) and maybe find a real fix for the problem. Of >> course, I still like my patch because it greatly decreases the time >> necessary for a reset (and the chance to hit the problem). > > Well, you can share your idea anytime. You already speculated that PHY > reset on 88e1116r is broken but it seems that is not true. The more > you share of your issue and the tries to fix it, the more likely is it > we can follow your patch immediately.
Sorry, but wild speculating doesn't help always. Otherwise I could mention several dozen possible reasons, starting from broken memory or other hw up to some memory corruption elsewhere in the kernel.
But I already have given a hint before, try what happens if you enable netconsole (compiled in) through the kernel commandline (netconsole=...). Maybe the ethernet on your dockstar will get stuck too.
> > Again, if you really want to find the real patch breaking Sheevaplug, > use git bisect.
That's silly if I already know a/the change which brings the problem to light. If I revert the mentioned commit the problem disapears. So why should I go through the pain to bisect stuff? I already have found the knob to kill the ethernet on that machine.
Regards,
Alexander Holler
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