NAK: [Utopic SRU][PATCH] Backport of DisplayPort 1.2 MST support

[Tim Gardner]

On 11/03/2014 07:26 AM, Dariusz Gadomski wrote:
> On Mon, Nov 03, 2014 at 07:03:15AM -0700, Tim Gardner wrote:
>> Of the 5 patches that I spot checked, none were from Linus' repo, and
>> are therefore _not_ upstream. Released distro kernels (such as Utopic)
>> largely adhere to upstream stable rules
>> (Documentation/stable_kernel_rules.txt). Even if these patches were
>> clean cherry-picks I'd be loathe to accept a patch set of this magnitude
>> into a stable kernel without extensive regression testing.
> 
> As I have mentioned in the cover letter this feature has been
> backported by David Airlie from the commits present in Linus' repo.
> Would it be more appropriate if I cherry-pick this directly from
> Linus's repo and resolving the conflicts myself?
> 
> What I based upon by putting 'upstream' there is the (upstream) token
> explanation available at [1]. I thought it is consistent with what is
> present in the patches.
> 

The content of the cover letter won't be relevant 6 months from now when
a stable maintainer has a patch conflict and is wondering where the heck
the patch causing the conflict came from. If it isn't from Linus' repo,
then is isn't upstream. So yes, a cherry-pick SHA1 is meaningful only
when it comes from Linus. His is the only repo that I trust to remain
immutable. Furthermore, stable rules indicate a patch (or backport
thereof) is not eligible unless it has been merged to Linus' repo.

>> Test results > from the bug report don't look encouraging.
> 
> Please note that only 1 comment in the bug report refers to this
> particular patchset [2] and the user found it working without any issues
> on Utopic.
> 
> Most of the comments were refering to trusty builds which don't offer
> the feature yet. As I don't posess the necessary hardware some negative
> feedback (again: not for this patchset for Utopic) from the community
> was expected.
> 
> [1] https://wiki.ubuntu.com/Kernel/Dev/StablePatchFormat
> [2] https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1104230/comments/52
> 

When making changes of this magnitude to a driver that affects a good
percentage of Ubuntu desktops, it is insufficient to merely test that
the new feature works on the one platform in question. In order to do
the whole job we have to test a representative sample of platforms to
ensure that we've not regressed. I'm not getting that from the bug report.

rtg
-- 
Tim Gardner tim.gardner at canonical.com