egl/drm: reinstate (kms_)swrast support

With earlier commit we've added a generic LIBGL_ALWAYS_SOFTWARE handling
yet did not consider that the existing codebase unconditionally errors
out when set. That was fixed with a latter commit, while the fix itself
added erroneous restriction for egl/drm.

As mentioned in the report - the feature was working for ages. It was a
Gnome developer who added kms_swrast support for gbm in the first place.

Admittedly kms_swrast is somewhat in the middle between traditional
swrast and HW drivers, regardless - reinstate support.

Fixes: 47273d7312c ("egl: set UseFallback if LIBGL_ALWAYS_SOFTWARE is set")
Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/165
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Acked-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4084>

diff --git a/src/egl/drivers/dri2/platform_drm.c b/src/egl/drivers/dri2/platform_drm.c
index d0ab172d65901d11e8b672c5e1054ce6f6e8d2bc..d25141a52a27b1a1e7f51e9b6d702184d2b5c2a6 100644 (file)
--- a/src/egl/drivers/dri2/platform_drm.c
+++ b/src/egl/drivers/dri2/platform_drm.c
@@ -695,10 +695,6 @@ dri2_initialize_drm(_EGLDriver *drv, _EGLDisplay *disp)
    struct gbm_device *gbm;
    const char *err;
 
-   /* Not supported yet */
-   if (disp->Options.ForceSoftware)
-      return EGL_FALSE;
-
    dri2_dpy = calloc(1, sizeof *dri2_dpy);
    if (!dri2_dpy)
       return _eglError(EGL_BAD_ALLOC, "eglInitialize");
@@ -732,7 +728,7 @@ dri2_initialize_drm(_EGLDriver *drv, _EGLDisplay *disp)
       goto cleanup;
    }
 
-   dev = _eglAddDevice(dri2_dpy->fd, false);
+   dev = _eglAddDevice(dri2_dpy->fd, disp->Options.ForceSoftware);
    if (!dev) {
       err = "DRI2: failed to find EGLDevice";
       goto cleanup;