[Mesa-dev] [PATCH v2] intel: Move the DRM uapi headers to a non-Intel location.

[Alex Deucher]

On Fri, Jun 30, 2017 at 3:02 PM, Eric Anholt <eric at anholt.net> wrote:
> Alex Deucher <alexdeucher at gmail.com> writes:
>
>> On Fri, Jun 30, 2017 at 12:40 PM, Lionel Landwerlin
>> <lionel.g.landwerlin at intel.com> wrote:
>>> On 30/06/17 17:14, Alex Deucher wrote:
>>>>
>>>> On Fri, Jun 30, 2017 at 12:02 PM, Eric Anholt <eric at anholt.net> wrote:
>>>>>
>>>>> Alex Deucher <alexdeucher at gmail.com> writes:
>>>>>
>>>>>> On Thu, Jun 29, 2017 at 11:42 AM, Eric Anholt <eric at anholt.net> wrote:
>>>>>>>
>>>>>>> I want to remove vc4's dependency on headers from libdrm as well, but
>>>>>>> storing multiple copies of drm_fourcc.h in our tree would be silly.
>>>>>>>
>>>>>>> v2: Update Android.mk as well, move distcheck drm*.h references to
>>>>>>>      top-level noinst_HEADERS.
>>>>>>>
>>>>>>> Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
>>>>>>> Reviewed-by: Daniel Stone <daniels at collabora.com>
>>>>>>> ---
>>>>>>>   Makefile.am                                      |  4 ++++
>>>>>>>   {src/intel/drm => include/drm-uapi}/README       |  0
>>>>>>>   {src/intel/drm => include/drm-uapi}/drm.h        |  0
>>>>>>>   {src/intel/drm => include/drm-uapi}/drm_fourcc.h |  0
>>>>>>>   {src/intel/drm => include/drm-uapi}/drm_mode.h   |  0
>>>>>>>   {src/intel/drm => include/drm-uapi}/i915_drm.h   |  0
>>>>>>>   src/intel/Android.vulkan.mk                      |  2 +-
>>>>>>>   src/intel/Makefile.am                            |  1 -
>>>>>>>   src/intel/Makefile.drm.am                        | 22
>>>>>>> ----------------------
>>>>>>>   src/intel/Makefile.sources                       |  6 ------
>>>>>>>   src/intel/Makefile.vulkan.am                     |  2 +-
>>>>>>>   src/mesa/drivers/dri/i965/Android.mk             |  4 ++--
>>>>>>>   src/mesa/drivers/dri/i965/Makefile.am            |  2 +-
>>>>>>>   13 files changed, 9 insertions(+), 34 deletions(-)
>>>>>>>   rename {src/intel/drm => include/drm-uapi}/README (100%)
>>>>>>>   rename {src/intel/drm => include/drm-uapi}/drm.h (100%)
>>>>>>>   rename {src/intel/drm => include/drm-uapi}/drm_fourcc.h (100%)
>>>>>>>   rename {src/intel/drm => include/drm-uapi}/drm_mode.h (100%)
>>>>>>>   rename {src/intel/drm => include/drm-uapi}/i915_drm.h (100%)
>>>>>>>   delete mode 100644 src/intel/Makefile.drm.am
>>>>>>
>>>>>>
>>>>>> I don't mean to pick on this patch specifically, but maybe it would
>>>>>> still make sense to depend on libdrm for the drm headers?  If not do
>>>>>> we want similar restrictions on updating these as we have for libdrm?
>>>>>
>>>>> Yes, we certainly have the same restrictions on updating headers (pull
>>>>> only things that have landed in airlied's drm-next, or possibly
>>>>> drm-misc-next if acked by airlied) as libdrm does.  That's
>>>>> "participating in kernel DRM development" rules, not libdrm rules.
>>>>
>>>> I'm not arguing about the fact that stuff has to land in drm-next,
>>>> etc. first, but there are pretty strict additional requirements as to
>>>> how they are updated:
>>>> https://cgit.freedesktop.org/mesa/drm/tree/include/drm/README
>>>> Do we want to enforce similar requirements in mesa?
>>>
>>>
>>> I think that's the idea, and what's in the README file of this commit.
>>> Maybe we need to update to to actually put the url of airlied's tree?
>>>
>>>>
>>>>> I don't think it makes sense to depend on libdrm if all you're using
>>>>>  From libdrm is the header that you can just put in the tree.
>>>>
>>>> I though we agreed that libdrm was supposed to be the canonical source
>>>> for these headers in userspace.  It just seems like we are going to
>>>> end up with a proliferation of these headers as various projects
>>>> decide to include them directly.
>>>
>>>
>>> I guess most driver developers didn't have an opinion at the time or didn't
>>> pay attention to the patch introducing
>>> https://cgit.freedesktop.org/mesa/drm/tree/include/drm/README
>>>
>>> Here is a pointer to the discussion with a different set of people, with
>>> Eric's answer which makes the best argument for this (in my opinion) :
>>>
>>> https://lists.freedesktop.org/archives/mesa-dev/2017-May/154491.html
>>
>> I don't necessarily agree with the rules for updating the headers in
>> libdrm.  I agree with Eric's statement that they should always be
>> compatible.  I like to be able to update the UAPI headers along with
>> the libdrm patch that uses them.  That said, I get yelled at every
>> time I try and do that, so I feel like we should apply that equally or
>> get rid of it.
>
> Sorry, what do you get yelled at for?  The only thing that would cause
> yelling, I believe, would be trying to merge (not just submit for
> review) libdrm/mesa/etc. patches updating the UAPI headers before the
> UAPI is in drm-next.

Not following the instructions here:
https://cgit.freedesktop.org/mesa/drm/tree/include/drm/README
when sending out patches that touch drm headers.  I.e., things like
partial updates to a driver header that just align to a specific
change you need.

Alex