[PATCH 0/9] uapi: drm: fixes for userspace compilation

[Emil Velikov]

On 17 November 2015 at 07:22, Michel Dänzer <michel at daenzer.net> wrote:
> On 14.11.2015 07:06, Emil Velikov wrote:
>> On 13 November 2015 at 21:36, Gabriel Laskar <gabriel at lse.epita.fr> wrote:
>>>
>>> There is still some issues on the headers, like the inclusion of drm.h.
>>>
>>> AFAIK, we should include "drm.h", in order to minimize the changes
>>> between linux/libdrm when importing, as the folders are not always the
>>> same (on Archlinux for example, drm.h is installed
>>> in /usr/include/libdrm/drm.h). This is not always the case in some of
>>> the headers:
>>>
>> I'm afraid we cannot do this. Things should just work without the
>> extra include directive (from your earlier example). We can easily fix
>> this and other issues in an automated way during import.
>
> [...]
>
>>> I can send patches for them too, I just need to know if this is useful,
>>> and not just nitpicking for you.
>>>
>> Everything but the s|drm/drm.h|drm.h| suggestion is pretty valid imho.
>
> What's the problem with changing
>
> #include <drm/drm.h>
>
> to
>
> #include "drm.h"
>
> in include/uapi/drm/*_drm.h? I recently made that change in radeon_drm.h
> and amdgpu_drm.h for the reason Gabriel mentioned above (in particular
> amdgpu_drm.h is now basically identical between the kernel and libdrm
> trees), and I haven't noticed any problems because of that.
>
I believe you're getting confused Michel. You did such change in
libdrm not the kernel... unless these changes haven't hit -next yet ?


Let me elaborate on the whole thing:

The kernel UAPI headers:
 - Used by the kernel modules and userspace(?)
 - Installed in /usr/include/drm
 - Many distributions do _not_ ship them
 - Broken for years (mostly fixed with Mikko's earlier patches)
 - For the above two reasons - most (all?) userspace uses the libdrm ones.

The libdrm headers:
 - Mostly preprocessed version of the above, used solely by userspace
 - Installed in /usr/include/libdrm
 - All distros ship them
 - Desperately out of sync wrt the above


With the above said:
 - I was thinking about hiding the UAPI ones, although Dave suggested
against it.
 - Doing s|drm/drm.h|drm.h| will break compilation:
   + for the kernel - as we don't add the foo/drm/ to the include directive,
   + for any hacked up userspace - very unlikely that they have the
include, considering that things work without it.
 - Differences wrt libdrm userspace - all of which can be handled with
simple sed
   + __KERNEL__ never defined so we can just ignore it
   + __user
   + drm/drm.h
   + others ?

Fwiw I still believe that the best solution is to "hide" the UAPI
headers, esp since they've been busted for a while. Then we can drop
the "drm/" and fix any in-kernel breakage. That said we will need to
convince Dave ;-)

Alternatively I suggest that we carry on with my earlier suggestion.
That is, unless someone comes with a better plan which doesn't involve
ignoring the problem :-P

Cheers,
Emil