[Buildroot] [RFC: 1/4] package/freescale-imx/imx-gpu-viv: BR2_PACKAGE_IMX_GPU_VIV_OUTPUT_{X11, WL} are libgl provider

[Yann E. MORIN <yann.morin.1998@free.fr>]

romain, All,

On 2021-01-07 12:04 +0100, Romain Naour spake thusly:
> libGL.so is installed when BR2_PACKAGE_IMX_GPU_VIV_OUTPUT_X11 or BR2_PACKAGE_IMX_GPU_VIV_OUTPUT_WL
> is selected, so declare it as a libgl provider.

I don;t think this is a good solution. At the very best it is a poor
workaround...

mesa3d will not install its headers if opengl is not enabled.

However, we always enable openGL:

    https://git.buildroot.org/buildroot/tree/package/mesa3d/mesa3d.mk#n160

    # Always enable OpenGL:
    #   - Building OpenGL ES without OpenGL is not supported, so alway keep opengl enabled.

The first part of thet comment was added back in 2014-04-2, with commit
384d601d4ea (package/mesa3d: always enable openGL, by your's truly), and
the second part was just an amendment to that, when we switched to using
meson as buildsystem, with commit f0483751dfa (package/mesa3d: switch
build system to meson).

So, the initial rationale for always enabling openGL is very old, and
mesa3d has changed quite a lot since then, so I'd like that we revisit
that assertion in the light of the new meson-based buildsystem.

And if imx-gpu-viv is enabled but mesa3d is not, then it would be
missing the GL headers. As such, it seems that mesa3d-headers should
then be used to provide those headers.

Unfortunately, we've made mesa3d-headers and mesa3d to conflict on
purpose.

But then does it make sense to have both imx-gpu-viv and mesa3d enabled
at the same time in the same configuration?

I.e. isn't the solution to that issue for imx-gpu-viv to select and
build-depend on mesa3d-headers when it needs the GL headers?

Regards,
Yann E. MORIN.

> Signed-off-by: Romain Naour <romain.naour@gmail.com>
> Cc: Gary Bisson <gary.bisson@boundarydevices.com>
> ---
> 
> Not related to this patch but mesa3d-demo doesn't build with imx-gpu-viv
> as GL provider. meta-freescale provide a patch that replace glWindowPos2iARB
> calls with glWindowPos2i but it was rejected by upstream.
> 
> https://github.com/Freescale/meta-freescale/blob/dunfell/recipes-graphics/mesa/mesa-demos/Replace-glWindowPos2iARB-calls-with-glWindowPos2i.patch
> ---
>  package/freescale-imx/imx-gpu-viv/Config.in      | 6 ++++++
>  package/freescale-imx/imx-gpu-viv/imx-gpu-viv.mk | 4 ++--
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/package/freescale-imx/imx-gpu-viv/Config.in b/package/freescale-imx/imx-gpu-viv/Config.in
> index cca2689905..4e53044d1d 100644
> --- a/package/freescale-imx/imx-gpu-viv/Config.in
> +++ b/package/freescale-imx/imx-gpu-viv/Config.in
> @@ -44,6 +44,7 @@ config BR2_PACKAGE_IMX_GPU_VIV_OUTPUT_X11
>  	select BR2_PACKAGE_XLIB_LIBXDAMAGE
>  	select BR2_PACKAGE_XLIB_LIBXEXT
>  	select BR2_PACKAGE_XLIB_LIBXFIXES
> +	select BR2_PACKAGE_HAS_LIBGL # libGL-x11.so
>  
>  comment "X11 backend needs Xorg package"
>  	depends on !BR2_PACKAGE_XORG7
> @@ -60,6 +61,7 @@ config BR2_PACKAGE_IMX_GPU_VIV_OUTPUT_WL
>  	select BR2_PACKAGE_LIBDRM
>  	select BR2_PACKAGE_WAYLAND
>  	select BR2_PACKAGE_HAS_LIBEGL_WAYLAND
> +	select BR2_PACKAGE_HAS_LIBGL # libGL-wl.so
>  
>  endchoice
>  
> @@ -72,6 +74,10 @@ config BR2_PACKAGE_IMX_GPU_VIV_OUTPUT
>  config BR2_PACKAGE_PROVIDES_LIBEGL
>  	default "imx-gpu-viv"
>  
> +config BR2_PACKAGE_PROVIDES_LIBGL
> +	default "imx-gpu-viv" if BR2_PACKAGE_IMX_GPU_VIV_OUTPUT_X11 || \
> +		BR2_PACKAGE_IMX_GPU_VIV_OUTPUT_WL
> +
>  config BR2_PACKAGE_PROVIDES_LIBGLES
>  	default "imx-gpu-viv"
>  
> diff --git a/package/freescale-imx/imx-gpu-viv/imx-gpu-viv.mk b/package/freescale-imx/imx-gpu-viv/imx-gpu-viv.mk
> index 6ae9aa7acc..f03415b336 100644
> --- a/package/freescale-imx/imx-gpu-viv/imx-gpu-viv.mk
> +++ b/package/freescale-imx/imx-gpu-viv/imx-gpu-viv.mk
> @@ -61,7 +61,7 @@ endif
>  
>  ifeq ($(IMX_GPU_VIV_LIB_TARGET),x11)
>  define IMX_GPU_VIV_FIXUP_PKGCONFIG
> -	for lib in egl gbm glesv1_cm glesv2 vg; do \
> +	for lib in egl gbm glesv1_cm glesv2 gl vg; do \
>  		ln -sf $${lib}_x11.pc $(@D)/gpu-core/usr/lib/pkgconfig/$${lib}.pc || exit 1; \
>  	done
>  endef
> @@ -70,7 +70,7 @@ endif
>  define IMX_GPU_VIV_INSTALL_STAGING_CMDS
>  	cp -r $(@D)/gpu-core/usr/* $(STAGING_DIR)/usr
>  	$(IMX_GPU_VIV_FIXUP_PKGCONFIG)
> -	for lib in egl gbm glesv1_cm glesv2 vg; do \
> +	for lib in egl gbm glesv1_cm glesv2 gl vg; do \
>  		$(INSTALL) -m 0644 -D \
>  			$(@D)/gpu-core/usr/lib/pkgconfig/$${lib}.pc \
>  			$(STAGING_DIR)/usr/lib/pkgconfig/$${lib}.pc; \
> -- 
> 2.25.4
> 
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