[PATCH 1/1] Documentation: drm: describing drm properties exposed by various drivers

Randy Dunlap rdunlap at infradead.org
Fri Aug 1 15:21:43 PDT 2014

On 08/01/14 05:58, Laurent Pinchart wrote:
> Hi Randy,
> On Thursday 31 July 2014 15:16:21 Randy Dunlap wrote:
>> On 05/12/14 11:04, Randy Dunlap wrote:
>>> On 05/12/2014 08:54 AM, Daniel Vetter wrote:
>>>> On Mon, May 12, 2014 at 08:23:45AM -0700, Randy Dunlap wrote:
>>>>> On 05/12/2014 01:58 AM, Daniel Vetter wrote:
>>>>>> On Mon, May 12, 2014 at 06:24:57PM +1000, Dave Airlie wrote:
>>>>>>>>> If we decide to go for property documentation inside the source code
>>>>>>>>> then I believe we'll have to create our own format, as creating a
>>>>>>>>> properties table from kerneldoc information extracted from comments
>>>>>>>>> is probably not possible.
>>>>>>>> Can comeone pick up the ball here and figure out what needs to be
>>>>>>>> done?
>>>>>>>> The reason why I want a central place for the documentation is to
>>>>>>>> force people to collaborate outside their own sandbox when adding
>>>>>>>> properties. Whether that's docbook or some text file I don't care so
>>>>>>>> much at this point. The fact that it's a central place should mandate
>>>>>>>> that the patches changing it will go through dri-devel and so
>>>>>>>> everyone should se them, and when adding new properties it would make
>>>>>>>> the patch author more likely to look around a bit before adding
>>>>>>>> another slighty incompatible version of the same property. If someone
>>>>>>>> has a better suggestion how to encforce this I'm all ears.
>>>>>>>> Of course this idea can still fail if our esteemed maintainer merges
>>>>>>>> stuff without checking for violations of this policy. Dave, any
>>>>>>>> thoughts on the subject?
>>>>>>> Yeah I'm happy to block merging stuff, if we can spot new properties
>>>>>>> when stuff is posted on dri-devel, so much the better,
>>>>>>> most drivers still send everything via dri-devel anyways, its only
>>>>>>> really Intel I have to worry about so far,
>>>>>> I'll enforce that all prop stuff gets cc: dri-devel and that it has
>>>>>> updates for the prop docs.
>>>>>>> But we should definitely add it to the new driver review checklist as
>>>>>>> well.
>>>>>>> I'm also on the side of this patch is ugly and makes my eyes burn,
>>>>>>> please please get a plan to use something else ASAP, I'm willing to
>>>>>>> merge this but I'm tempted to give it a lifetime of a kernel or two
>>>>>>> before I burn it.
>>>>>> Ok, I'll try to move "make kerneldoc suck less" up the task list and
>>>>>> maybe find someone to do it for me internally ;-)
>>>>> I certainly have no objections to making kerneldoc suck less.
>>>>> There was already an attempt to use asciidoc (like git uses) for
>>>>> kernel-doc (a few years ago, by Sam Ravnborg).  I support(ed) that
>>>>> effort.
>>>> Hm, do you have pointers to those? My google-fu seems lacking ...
>>> I googled for /kernel doc asciidoc ravnborg/ and found several hits for
>>> them.
>>>> Ok, let's move this to the top and start discussions. The past few months
>>>> I've written piles of kerneldoc comments for the DRM DocBook (all pulled
>>>> in as kerneldoc, docbook .tmpl has just the chapter structure). DOC:
>>>> sections are really useful to pull all the actual documentation out of
>>>> the docbook xml into kerneldoc.
>>>> But I've also done piles of docs for intel-gpu-tools, which is using
>>>> gtkdoc. And there are some clear deficiencies:
>>>> - No markdown for inline coments. Lack of lists and tables is hurting
>>>>   especially badly. If we add this (and I don't care one iota whether
>>>>   it's
>>> Yes, I've tried to add lists to kernel-doc notation but have failed so
>>> far.
>>>>   markdown or asciidoc or something else as long as it's readable plain
>>>>   text in comments) we should be able to move all the existing docbook
>>>>   xml paragraphs/lists/tables into kerneldoc comments.
>>>> - Automatic cross-referencing of functions. If you place e.g. function()
>>>>   or #struct anywhere in a documentation comment gtk-doc automatically
>>>>   inserts a hyperlink to the relevant documentation page across the
>>>>   entire project. Really powerful and makes overview sections much more
>>>>   useful entry points for beginners since they can easily jump back&forth
>>>>   betweeen the high-level overview and low-level per-function
>>>>   documentation.
>>> That's a nice-to-have IMO, but a really nice one.
>>>> - In a really perfect world it would help if kerneldoc could collect
>>>>   structure member kerneldoc from per-member comments. Especially for
>>>>   large structures with lots of comments this would bring the kerneldoc
>>>>   and struct member much closer together.
>>>> So that's my wishlist.
>>>>> OTOH, I would only want to add another way to do kernel-doc if it can be
>>>>> a full replacement for all of our docbook usage, i.e., it should provide
>>>>> a way that we can eliminate docbook and stop using it completely.
>>>> Hm, I don't mind docbook at all, as long as all the real content is
>>>> embedded into source files as kerneldoc and the docbook template just
>>>> pulls in all the right bits and pieces. Even gtkdoc allos you to do that
>>>> and pull in the different libararies (== header files with declarations
>>>> for C) in the order you want. So imo the docbook toolchain is good enough
>>>> for my needs.
>>>> Or what do you mean by getting rid of all docbook usage?
>>> I meant no docbook style sheets, no 'xmlto', the whole ball of wax.
>>> But primarily I don't want to see drivers/video/ using one set of doc
>>> tools and drivers/media/ using another set and drivers/xyz/ using its own
>>> set of tools, etc. etc. etc.
>> Hi Daniel and others,
>> I don't know what your plans are for drm docs (tables, etc.), but I think
>> that I misspoke above.   My primary/major concern is that there be some
>> useful documentation.  What form or format it is in is secondary.
> I agree with you, there's no reason to block your patch just because we might 
> get a better documentation tool at a still unknown point in the future. 
> Daniel, are you fine with merging the documentation in DocBook format for now 
> ?
> Randy, could you please check whether your patch still applies and rebase and 
> resubmit it if it doesn't ?

Hi Laurent,
What patch are you referring to here?


>> It's not a good thing that media DocBook is so different from all of the
>> others, but it's OK.
>> It's not a good thing that drivers/lguest/ uses its own tools to extract
>> comments from source files to create documentation, but it's OK -- at least
>> it generates some (hopefully useful) documentation.
>> I also note that a new autofs doc file (not yet merged) uses markdown.
>> Please feel free to use kernel-doc or markdown or asciidoc or plain text. :)
>> or even your own tools, even though that is less preferred.


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