On Mon, Jan 18, 2016 at 11:36:25PM -0800, Greg KH wrote:

On Mon, Jan 18, 2016 at 05:34:32PM +0000, John Whitmore wrote:

quoted

I built and installed v4.4 on my laptop but Suspend no longer worked so I set
about doing a git bisect to find the source of the problem. I've never had
cause to use bisect before so if nothing else I'll have learned something. 

Anyhow got to an end point in git bisect of:

john at bamboo:> git bisect bad
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[b8b2c7d845d57f7a4b9f1f941f24728165e27626] base/platform: assert that dev_pm_domain callbacks are called unconditionally

I was actually chuffed I got that far and it took a while as I was doing a
"make mrproper" each time. I sort of assumed that I could just bisect and do a
make, which would work out what it had to recompile, but then thought maybe
that was a bit of an assumption. Be a shame to do all that work and find out
you had to clean up a bit between builds.

You don't have to, a simple 'make oldconfig' and 'make' should do just
fine.

quoted

I'm sure that this problem has been found and a patch submitted by now as it
seems to have been from months ago. But assuming neither had occured and this
was a new discovery how do you check for a reported bug? Do you search mailing
list for that commit number, or a part of that commit number?

Yes, this bug has been found, and a fix was submitted, I just haven't
taken it yet, sorry.  I will do so after 4.5-rc1 is out.  If you search
the linux-kernel mailing list for:
	Subject: [PATCH] base/platform: Fix platform drivers with no probe callback (ex alarmtimer)

you can find the fix.

Sorry you hit this, I'll get it merged soon.

Hey not at all, I'm glad I did hit the problem. I'm re-reading LDD for probably
the third time and soaking up a little bit more, before I start work on a USB
driver. I was glad of the distraction and happy to try see if I could find the
source of the problem. If I wasn't busy I might even try and see if I could
debug it and get my own fix, just for the exercise and learning. Who knows
maybe it'll be a slow weekend ;-)

greg k-h