Coherent surfaces make only sense if the host renders to them using accelerated apis. Without 3d the entire content of dumb buffers stays in the guest making all of the extra work they're doing to synchronize between guest and host useless.

Configurations without 3d also tend to run with very low graphics memory limits. The pinned console fb, mob cursors and graphical login manager tend to run out of 16MB graphics memory that those guests use.

Fix it by making sure the coherent dumb buffers are only used on configs with 3d enabled.

Signed-off-by: Zack Rusin zack.rusin@broadcom.com Fixes: d6667f0ddf46 ("drm/vmwgfx: Fix handling of dumb buffers") Reported-by: Christian Heusel christian@heusel.eu Closes: https://lore.kernel.org/all/0d0330f3-2ac0-4cd5-8075-7f1cbaf72a8e@heusel.eu Cc: Broadcom internal kernel review list bcm-kernel-feedback-list@broadcom.com Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v6.9+ Cc: Maaz Mombasawala maaz.mombasawala@broadcom.com Cc: Martin Krastev martin.krastev@broadcom.com --- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c index 8ae6a761c900..1625b30d9970 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -2283,9 +2283,11 @@ int vmw_dumb_create(struct drm_file *file_priv, /* * Without mob support we're just going to use raw memory buffer * because we wouldn't be able to support full surface coherency - * without mobs + * without mobs. There also no reason to support surface coherency + * without 3d (i.e. gpu usage on the host) because then all the + * contents is going to be rendered guest side. */ - if (!dev_priv->has_mob) { + if (!dev_priv->has_mob || !vmw_supports_3d(dev_priv)) { int cpp = DIV_ROUND_UP(args->bpp, 8);

switch (cpp) {