Re: Add support for recent lenovo thinkpad HKEYS(Wifi/video swicth etc) buttons

[Joakim Tjernlund <Joakim.Tjernlund@infinera.com>]

On Thu, 2016-09-15 at 07:59 +0200, greg@kroah.com wrote:
> On Wed, Sep 14, 2016 at 07:07:36PM +0000, Joakim Tjernlund wrote:
> > 
> > On Wed, 2016-09-14 at 20:10 +0200, greg@kroah.com wrote:
> > > 
> > > On Wed, Sep 14, 2016 at 05:57:30PM +0000, Joakim Tjernlund wrote:
> > > > 
> > > > 
> > > > On Wed, 2016-09-14 at 19:08 +0200, greg@kroah.com wrote:
> > > > > 
> > > > > 
> > > > > On Wed, Sep 14, 2016 at 04:13:52PM +0000, Joakim Tjernlund wrote:
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > > On Wed, 2016-09-14 at 16:35 +0200, greg@kroah.com wrote:
> > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > On Wed, Sep 14, 2016 at 12:00:04PM +0000, Joakim Tjernlund wrote:
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > On Wed, 2016-09-14 at 13:54 +0200, Greg KH wrote:
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > On Wed, Sep 14, 2016 at 06:44:50AM +0000, Joakim Tjernlund wrote:
> > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > 
> > > > > > > > > > These patches are picked from Linux upstream repo and applies directly on 4.4.x
> > > > > > > > > > Please excuse the attachments but git send email does not work for us ATM.
> > > > > > > > > 
> > > > > > > > > What is the git commit ids of these patches in Linus's tree?
> > > > > > > > 0002-thinkpad_acpi-Add-support-for-keyboard-backlight.patch:
> > > > > > > > 6cf4a2c575b4797b967a575b6274e0e40c5f88f1
> > > > > > > 
> > > > > > > I do not see that git commit id in Linus's tree, do you?
> > > > > > 
> > > > > > ehh, no. I used my 4.4 branch instead of linux master, sorry
> > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 0003-thinkpad_acpi-Remove-ambiguous-logging-for-Unsupport.patch:
> > > > > > > > 85342b97c2ee2a94a31ea5d59d58cdfd1f045e2a
> > > > > > > 
> > > > > > > Nor this one.  I stopped here, assuming that your other ids aren't
> > > > > > > correct either :(
> > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 0004-thinkpad_acpi-Silence-an-uninitialized-variable-warn.patch:
> > > > > > > > dcf95a1961f9614eee09066f8148813772ad4268
> > > > > > > > 0005-thinkpad_acpi-save-kbdlight-state-on-suspend-and-
> > > > > > > > res.patch:1c6c99c6767035761d17aeecaf0224934ccd00fb
> > > > > > > > 0006-thinkpad_acpi-Add-support-for-HKEY-version-0x200.patch:
> > > > > > > > 1bc0df534d11c8c9c97e1e8315b7d22bf034c8d2
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > 
> > > > > > > > > And what happened to the other patches in this series?
> > > > > > > > >  
> > > > > > > > The first one was inappropriate, that is why 0001 is missing.
> > > > > > > 
> > > > > > > That's pretty strange of you to force us to guess what is going on here,
> > > > > > > would you like to get a series like this and wonder why something
> > > > > > > obvious like this is gone?
> > > > > > 
> > > > > > Yes, it was inconsiderate of me, sorry.
> > > > > > 
> > > > > > Trying to do better I figured I should generate a new series from Linus tree but
> > > > > > I cannot figure out how generate a series from commits that are non sequential in Linux tree.
> > > > > > git format path does not have a syntax for that from what I can tell, any ideas?
> > > > > 
> > > > > Why not just send us the git commit ids that you want applied?  That's
> > > > > all we need.
> > > > >  
> > > > Oh, didn't occur to me. Here we go(ltes se fi I got it right this time :)
> > > > 
> > > > bb28f3d51ff5e1be541d057708011cc1efe6fae9 - thinkpad_acpi: Add support for keyboard backlight
> > > 
> > > How does this commit meet the Documentation/stable_kernel_rules.txt
> > > requirements?  It's a new feature, and too big, why would we add it to
> > > an old kernel like this one?  What's wrong with just using a newer
> > > kernel for a feature like this?
> > > 
> > > > 
> > > > 
> > > > 15c75626f0999cce8357c8bf8578247134032acb - thinkpad_acpi: Remove ambiguous logging for "Unsupported
> > > > brightness interface"
> > > > a7718360d91eedbedd58978ec8fff4a67a866f86 - thinkpad_acpi: Silence an uninitialized variable warning
> > > > afcedebc6a094224973534f43b396bbbf33fe44e - thinkpad_acpi: save kbdlight state on suspend and restore
> > > > it on
> > > > resume
> > > 
> > > Are these 3 fixes for the first one?
> > > 
> > > > 
> > > > 
> > > > 0118c2d3eac0545d4095877e5a015b5dc763b3c2 - thinkpad_acpi: Add support for HKEY version 0x200
> > > 
> > > Again, another feature :(
> > 
> > hmm, this was the one I really wanted as then wifi/video switch
> > buttons work on our Lenovo laptops we recently bought to replace old
> > HPs. I did not think this was to regard as a new feature, just a fix
> > to make the same buttons work as on other models, sorry.
> 
> It's a new feature for that model of laptop, otherwise we would be
> backporting everything all the time :(

Yes, but allowing new HW to work properly in older kernels was an exception or at least so I thought.
If here is a new minor version of the e1000 ethernet device which needs a few tweaks to
function on older kernels, do you not accept patches for that?

> 
> > 
> > The other patches were just there to make sure I didn't run inte
> > conflicts I didn't want to resolve.  They all made sense except for
> > maybe the one adding keyboard backlight. 
> > 
> > > 
> > > And why aren't we cc:ing the maintainers of this subsystem?
> > 
> > Right, they are now. If you and/or maintainers do feel this is
> > inappropriate for stable I will just carry them my self until the next
> > major stable kernel is released.
> 
> What is wrong with 4.7-stable kernels?  Why are you "stuck" at 4.4?
> 

Non LTS kernels are fairly short lived. First you have wait for a few patch levels(say >=5) before
one can consider the kernel fairly stable. After that there isn't that many release before it retired
and you have to look for the next stable kernel. 

Each time you migrate your kernel config between major releases there is a risk something is
mis migrated so one has to spend some time to review/test the kernel.
So I stay on LTS were I can and only systems really needing something newer gets a non LTS kernel.

Note that this our company kernel, used on > 100 boxes and it is not uncommon that something
breaks somewhere after a major kernel upgrade, usually because I missed some kernel config.

  Jocke