[hrtimers] Re: Regression affecting b43 LP-PHY card

[Rafał Miłecki]

2011/5/10 Rafał Miłecki <zajec5 at gmail.com>:
> 2011/5/10 John Stultz <john.stultz at linaro.org>:
>> On Tue, 2011-05-10 at 20:57 +0200, Rafał Miłecki wrote:
>>> W dniu 10 maja 2011 00:52 użytkownik Rafał Miłecki <zajec5 at gmail.com> napisał:
>>> > In this situation we decided to bisect. I was a little afraid of last
>>> > merges so we took older 2.6.38 as GOOD (we tested this twice) and
>>> > wireless-testing commit before my ssb changes as BAD. Today Juan
>>> > finished bisecting kernel:
>>> > http://pastebin.com/HSKbRzpB
>>> >
>>> > According to his bisection the first bad commit is
>>> > e06383db9ec591696a06654257474b85bac1f8cb [0]:
>>> > hrtimers: extend hrtimer base code to handle more then 2 clockids
>>> >
>>> > Does it make any sense to you? Could this be some timing issue?
>>> >
>>> > It was too late to test this today, we (Juan) will work on this
>>> > tomorrow. It's impossible to revert this commit from HEAD of
>>> > wireless-testing, so my idea is to checkout commit, test, revert,
>>> > test.
>>> >
>>> > Did anyone else experience any similar problems with latest wireless-testing?
>>> >
>>> >
>>> > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e06383db9ec591696a06654257474b85bac1f8cb
>>>
>>> Today Juan checkouted commit e06383db9ec591696a06654257474b85bac1f8cb
>>> and tested it. He was disconnected really soon.
>>>
>>> Then he reverted e06383db9ec591696a06654257474b85bac1f8cb and tested
>>> again. Connection was stable, he downloaded 2GB file over network.
>>>
>>>
>>> John S.: your commit does not touch Broadcom card directly, but it
>>> seems it somehow affects it. I suspect there can be some timing issue.
>>> Do you have any idea what could it be, how can we debug this?
>>
>> Sorry for the trouble!
>>
>> My commit exposed a few spots where hrtimers were being initialized
>> before hrtimer_init is called, which caused problems. Thomas provided a
>> solution that makes such behavior still function ok:
>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=ce31332d3c77532d6ea97ddcb475a2b02dd358b4
>>
>> Let me know if the issue is still reproducible with Linus' latest git
>> tree.
>
> We were using wireless-testing git tree, commit:
> 1e664a777e5eb4b23e65e76fbeadd2376fe8d8d8
>
> I can not see ce31332d3c77532d6ea97ddcb475a2b02dd358b4 it git log.
> I'll apply and test, thanks!

I can confirm updated wireless-testing resolves this issue!

Too bad Juan spent 2-3 days on bisecting on his Atom... but at least
we came and met ready fix. It could be pain to find a solution with
out feedback only. I'm aware it was not very detailed.

Thanks for your help :)

-- 
Rafał