[PATCH 1/2] glamor: add support for allocating linear buffers

[Dave Airlie]

On 19 June 2015 at 02:02, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> On 15 June 2015 at 05:08, Michel Dänzer <michel at daenzer.net> wrote:
>> On 12.06.2015 08:48, Dave Airlie wrote:
>>> We need this for doing USB offload scenarios using glamor
>>> and modesetting driver.
>>>
>>> unfortunately only gbm in mesa 10.6 has support for the
>>> linear API.
>>>
>>> Signed-off-by: Dave Airlie <airlied at redhat.com>
>>> ---
>>>  configure.ac                  |  5 +++++
>>>  glamor/glamor.h               |  3 ++-
>>>  glamor/glamor_egl.c           |  5 ++++-
>>>  glamor/glamor_egl_stubs.c     |  2 +-
>>>  glamor/glamor_fbo.c           | 10 +++++-----
>>>  hw/xwayland/xwayland-glamor.c |  2 +-
>>>  include/dix-config.h.in       |  3 +++
>>>  7 files changed, 21 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/configure.ac b/configure.ac
>>> index f760730..d0908e5 100644
>>> --- a/configure.ac
>>> +++ b/configure.ac
>>> @@ -2105,6 +2105,11 @@ if test "x$GLAMOR" = xyes; then
>>>       if test "x$GBM" = xyes; then
>>>               AC_DEFINE(GLAMOR_HAS_GBM, 1,
>>>                         [Build glamor with GBM-based EGL support])
>>> +             PKG_CHECK_MODULES(GBM_HAS_LINEAR, "gbm >= 10.6.0", [GBM_HAS_LINEAR=yes], [GBM_HAS_LINEAR=no])
>>> +             if test "x$GBM_HAS_LINEAR" = xyes; then
>>> +                     AC_DEFINE(GLAMOR_HAS_GBM_LINEAR,  1,
>>> +                       [Build glamor/gbm has linear support])
>>> +             fi
>>
>> It would be better to use AC_CHECK_DECL for this, as is done in
>> xf86-video-amdgpu. That way it does the right thing even if somebody
>> backports GBM_BO_USE_LINEAR to an older version of Mesa.
>>
> Fwiw I second this suggestion. As we know GBM is an API and others may
> provide alternative implementation of it (for example CrOS has
> minigbm). Imho using the mesa version in (m)any of the pc files is a
> bug, which should be addressed, rather than relied upon.
>

I'll change it because I prefer the suggestion,

but GBM is both an API and an ABI, so really the pc.in represents
the API version, so any compatible API should use the mesa version
in its gbm.pc file until such time as someone splits the gbm API
out into a separate project, at which point you'd want to continue
the versioning from the mesa point to avoid epochs. So I don't
take your argument, the API version is what we ship in the gbm.pc
file, compatible implementations should make the same API changes
in their same versions.

Now the problem I don't solve here, is how to know if the GBM
ABI supports passing the linear flag in, since we don't bump
the library version often, and I've no idea if there is any nice
way to make it discoverable.

Dave.