kdbus and Fedora

[Harald Hoyer]

On 05.05.2015 20:28, Harald Hoyer wrote:
> On 05.05.2015 19:50, Josh Boyer wrote:
>> Hi All,
>>
>> Harald and I were recently talking about kdbus and how it plays into
>> Fedora.  Right now, the kernel-playground COPR is carrying the kdbus
>> patches, but that isn't widely used and isn't included in a broad test
>> base. Obviously our distribution is heavily entwined with D-Bus and we
>> were looking to see if it was possible to help kdbus testing and
>> development by doing some kind of integration within Fedora itself.  I
>> promised Harald I would talk it over with the other Fedora kernel
>> maintainers and after a brief discussion we came up with the following
>> possible proposal.
>>
>> If Fedora were to carry kdbus in any form, the following things would
>> be required:
>>
>> 1) There would be a single canonical location to track kdbus
>> development.  After talking with Harald, that should be the upstream
>> tree that gregkh is using to submit patches.
>>
>> 2) Harald's team (systemd, etc) would commit to testing the system
>> both with and without kdbus active.  Obviously we do not want to
>> enforce reliance on something as core critical as kdbus while it is
>> still being actively developed upstream.  That could cause a lot of
>> deviation down the road and it isn't the aim here.
>>
>> 3) kdbus would only be carried in the rawhide branch until it is
>> merged upstream.  As a concrete example, if kdbus was not merged in
>> the upstream kernel at the time rel-eng creates the F23 branches, then
>> Fedora 23 will never get kdbus.  It will be carried in rawhide and
>> rawhide only until it's accepted upstream.  The maintainers actually
>> hope this does get merged but we want to make sure we are prepared to
>> drop this without causing too much trouble if needed.
>>
>> 4) After discussing a bit with the rest of the Fedora kernel
>> maintainers, we would carry an additional patch that would require
>> 'kdbus-enabled' to be specified before the kernel would allow kdbus to
>> be loaded (or similar mechanism).  This would focus the main testing
>> effort for all the default images to remain as they are today, while
>> easily allowing the plumbing layer developers access to kdbus for
>> their enablement testing.
>>
>> These conditions would hopefully help the Fedora kernel maintainers
>> avoid some of the pitfalls of carrying a large chunk of out of tree
>> code and if they're all met we feel fairly comfortable with doing
>> this.  We wanted to send this out for a bit wider discussion and
>> review before proceeding with it, and I agreed to start this thread so
>> here we are.
>>
>> Harald, does the above look like what you were envisioning when we
>> talked earlier?
>>
>> josh
>>
> 
> Looks very good except for point 4, where we wanted to enable kdbus by default
> and have a "kdbus=0" command line option.
> 
> CC'ing the kdbus folks...
> 

btw, currently the kdbus module is only loaded by systemd, if you specify
"kdbus" on the kernel command line.