[PATCH wayland-web 7/7] Description of requirements not exactly right, DRI2 not needed in most cases

[Pekka Paalanen]

On Fri, 23 May 2014 18:54:39 -0700
Bill Spitzak <spitzak at gmail.com> wrote:

> From: Bill Spitzak <wspitzak at oblong.com>
> 
> ---
>  building.html |   23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/building.html b/building.html
> index 7f0c4b4..de721b5 100644
> --- a/building.html
> +++ b/building.html
...
> @@ -35,24 +35,31 @@ Pi</a>, see <a href="raspberrypi.html">Raspberry Pi build guide</a>.</li>
>  
>  <h2>Hardware / Drivers</h2>
>  
> -<p>X output requires DRI2.  DRM output (without X) requires Kernel Mode
> +<p>X output requires the X server to support DRI2 for clients that use
> +EGL for rendering. However most Weston clients can fall back to SHM
> +rendering if EGL is not available. Therefore you can use most
> +of Weston on non-DRI2 X servers, such as nVidia.</p>
> +
> +<p>DRM output (without X) requires Kernel Mode
>  Setting (KMS) and the page flip ioctl.  These are supported by:</p>

I suppose this refers to the DRI2 protocol for X11. I believe it is an
internal detail in getting Mesa EGL working properly under X11 for
Weston itself. This doesn't apply to totally different graphics stacks
like the Nvidia proprietary.

This has nothing to do with Wayland clients or Weston demo apps,
though. "The EGL" for Wayland clients is a different EGL platform than
what the compositor uses, and is mostly orthogonal. For instance, even
if the compositor does not have EGL available, Wayland apps may still
use EGL with a software renderer (in Mesa's case this is currently
implemented in egl_gallium.so).

Xwayland is yet another story.

Maybe it would be best to not change the text here. If you want, you
can add a separate bullet point for the nvidia proprietary driver
telling when it got EGL support for both 32 and 64 bit machines, and
that it could allow to run Weston only with the x11-backend, and
without support for hardware accelerated clients/apps. You got this
setup to work, right? (If you have to use --use-pixman for Weston, then
this is *not* working and should not be mentioned.)

To me it still seems a pretty big loss of features compared to a fully
working stack.


Thanks,
pq