drm: omapdrm: Do no allocate non-scanout GEMs through DMM/TILER

On devices with DMM, all allocations are done through either DMM or TILER.
DMM/TILER being a limited resource means that such allocations will start
to fail before actual free memory is exhausted. What is even worse is that
with time DMM/TILER space gets fragmented to the point that even if we have
enough free DMM/TILER space and free memory, allocation fails because there
is no big enough free block in DMM/TILER space.

Such failures can be easily observed with OMAP xorg DDX, for example -
starting few GUI applications (so buffers for their windows are allocated)
and then rotating landscape<->portrait while closing and opening new
windows soon results in allocation failures.

Fix that by mapping buffers through DMM/TILER only when really needed,
like, for scanout buffers.

Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1642587791-13222-4-git-send-email-ivo.g.dimitrov.75@gmail.com

diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
index 41c1a6d..cf57179 100644 (file)
--- a/drivers/gpu/drm/omapdrm/omap_gem.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem.c
@@ -821,10 +821,12 @@ int omap_gem_pin(struct drm_gem_object *obj, dma_addr_t *dma_addr)
                        if (ret)
                                goto fail;
 
-                       if (priv->has_dmm) {
-                               ret = omap_gem_pin_tiler(obj);
-                               if (ret)
-                                       goto fail;
+                       if (omap_obj->flags & OMAP_BO_SCANOUT) {
+                               if (priv->has_dmm) {
+                                       ret = omap_gem_pin_tiler(obj);
+                                       if (ret)
+                                               goto fail;
+                               }
                        }
                } else {
                        refcount_inc(&omap_obj->pin_cnt);
@@ -861,6 +863,8 @@ static void omap_gem_unpin_locked(struct drm_gem_object *obj)
                        kfree(omap_obj->sgt);
                        omap_obj->sgt = NULL;
                }
+               if (!(omap_obj->flags & OMAP_BO_SCANOUT))
+                       return;
                if (priv->has_dmm) {
                        ret = tiler_unpin(omap_obj->block);
                        if (ret) {