[PATCH xf86-video-dummy] Add glamor acceleration which enables native OpenGL support

[Emil Velikov]

On 7 March 2017 at 03:53, Qiang Yu <Qiang.Yu at amd.com> wrote:
> Enable glamor acceleration in xorg.conf by:
> Section "Device"
>   ...
>   Driver "dummy"
>   Option "Render" "/dev/dri/renderD128"
>   ...
> EndSection
>
> GPU is chosen by the Render option which specifies the render
> node of the GPU DRM device.
>
> We could use the dumb buffer instead of gbm buffer as the
> screen front buffer. But dumb buffer requires open
> /dev/dri/cardx which has the limitation of only one instance
> of OpenGL enabled xserver can start.
>
> With gbm buffer, we can use /dev/dri/renderDx which has no
> limitation on the number of OpenGL enabled xserver and even
> won't conflict with a "real" xserver using radeon/amdgpu DDX.
>
> Due to using renderDx, only DRI3 OpenGL is supported.
>
> DGA is disabled when glamor is enabled, we can enable it with
> new gbm_bo_map/unmap API, but consider a more effiction way
> is just using DRI3BufferFromPixmap for the root window pixmap.
>
> Signed-off-by: Qiang Yu <Qiang.Yu at amd.com>
> ---
>  configure.ac       |  26 ++++++++++
>  src/Makefile.am    |   7 ++-
>  src/dummy.h        |   9 ++++
>  src/dummy_dga.c    |   3 ++
>  src/dummy_driver.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++-----
>  5 files changed, 176 insertions(+), 12 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index 4eb7fae..7239b63 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -68,6 +68,32 @@ AM_CONDITIONAL([DGA], [test "x$DGA" = xyes])
>  # Obtain compiler/linker options for the driver dependencies
>  PKG_CHECK_MODULES(XORG, [xorg-server >= 1.4.99.901] xproto fontsproto $REQUIRED_MODULES)
>
> +# Check glamor support
> +AC_ARG_ENABLE(glamor,
> +             AS_HELP_STRING([--disable-glamor],
> +                            [Disable glamor, a new GL-based acceleration [default=enabled]]),
> +             [GLAMOR="$enableval"],
> +             [GLAMOR=yes])
> +
> +SAVE_CPPFLAGS="$CPPFLAGS"
> +CPPFLAGS="$CPPFLAGS $XORG_CFLAGS"
> +if test "x$GLAMOR" != "xno"; then
> +       AC_CHECK_HEADERS([glamor.h], , [GLAMOR=no], [#include "xorg-server.h"])
> +fi
> +CPPFLAGS="$SAVE_CPPFLAGS"
> +
> +if test "x$GLAMOR" != "xno"; then
> +       PKG_CHECK_MODULES(GBM, [gbm], , [GLAMOR=no])
> +fi
> +
> +AC_MSG_CHECKING([whether to include GLAMOR support])
> +AC_MSG_RESULT([$GLAMOR])
> +
> +if test "x$GLAMOR" != "xno"; then
> +        AC_DEFINE(USE_GLAMOR, 1, [Enable glamor acceleration])
> +fi
> +AM_CONDITIONAL(GLAMOR, test x$GLAMOR != xno)
> +
The idea is cool, but the above looks wrong/broken.

You want to AC_MSG_ERROR if the the option is set to "yes" and it's
not available. Currently one silently ignores it, which is not good.

-Emil