[Mesa-dev] [PATCH v6] egl/dri2: implement platform_surfaceless

[Chad Versace]

On Fri 12 Jun 2015, Zach Reizner wrote:
> From: Haixia Shi <hshi at chromium.org>
> 
> The surfaceless platform is for off-screen rendering only. Render node support
> is required.
> 
> Only consider the render nodes. Do not use normal nodes as they require
> auth hooks.
> 
> v3: change platform_null to platform_surfaceless
> v4: make libdrm required for surfaceless
> v5: remove modified include guards with defined(HAVE_SURFACELESS_PLATFORM)
> v6: use O_CLOEXEC for drm fd
> 
> Signed-off-by: Haixia Shi <hshi at chromium.org>
> Signed-off-by: Zach Reizner <zachr at google.com>
> ---
>  configure.ac                                |   6 +
>  src/egl/drivers/dri2/Makefile.am            |   5 +
>  src/egl/drivers/dri2/egl_dri2.c             |   7 ++
>  src/egl/drivers/dri2/egl_dri2.h             |   3 +
>  src/egl/drivers/dri2/platform_surfaceless.c | 171 ++++++++++++++++++++++++++++
>  src/egl/main/Makefile.am                    |   4 +
>  src/egl/main/egldisplay.c                   |   3 +-
>  src/egl/main/egldisplay.h                   |   1 +
>  8 files changed, 199 insertions(+), 1 deletion(-)
>  create mode 100644 src/egl/drivers/dri2/platform_surfaceless.c


> +#ifdef O_CLOEXEC
> +      dri2_dpy->fd = open(card_path, O_RDWR | O_CLOEXEC);
> +      if (dri2_dpy->fd < 0 && errno == EINVAL)
> +#endif
> +      {
> +         dri2_dpy->fd = open(card_path, O_RDWR);
> +         if (dri2_dpy->fd >= 0)
> +            fcntl(dri2_dpy->fd, F_SETFD, fcntl(dri2_dpy->fd, F_GETFD) |
> +               FD_CLOEXEC);
> +      }

The #ifdef and fallback path here look strange to me because Linux has
supported O_CLOEXEC for a loooong time. After grepping for O_CLOEXEC,
though, I discovered that this pattern is common throughout Mesa. So...
ok.

I was initially worried that dri2_terminate() might not properly tear
down the display, but I convinced myself the code is correct.

Reviewed-by: Chad Versace <chad.versace at intel.com>

If no one objects, I'll commit this Monday afternoon.