+++ /dev/null
-From f7aef1c207092770d06d0df21dceafdca2b49c39 Mon Sep 17 00:00:00 2001
-From: Boris Brezillon <boris.brezillon@bootlin.com>
-Date: Mon, 30 Apr 2018 15:32:32 +0200
-Subject: drm/vc4: Make sure vc4_bo_{inc,dec}_usecnt() calls are balanced
-
-From: Boris Brezillon <boris.brezillon@bootlin.com>
-
-commit f7aef1c207092770d06d0df21dceafdca2b49c39 upstream.
-
-Commit b9f19259b84d ("drm/vc4: Add the DRM_IOCTL_VC4_GEM_MADVISE ioctl")
-introduced a mechanism to mark some BOs as purgeable to allow the driver
-to drop them under memory pressure. In order to implement this feature
-we had to add a mechanism to mark BOs as currently used by a piece of
-hardware which materialized through the ->usecnt counter.
-
-Plane code is supposed to increment usecnt when it attaches a BO to a
-plane and decrement it when it's done with this BO, which was done in
-the ->prepare_fb() and ->cleanup_fb() hooks. The problem is, async page
-flip logic does not go through the regular atomic update path, and
-->prepare_fb() and ->cleanup_fb() are not called in this case.
-
-Fix that by manually calling vc4_bo_{inc,dec}_usecnt() in the
-async-page-flip path.
-
-Note that all this should go away as soon as we get generic async page
-flip support in the core, in the meantime, this fix should do the
-trick.
-
-Fixes: b9f19259b84d ("drm/vc4: Add the DRM_IOCTL_VC4_GEM_MADVISE ioctl")
-Reported-by: Peter Robinson <pbrobinson@gmail.com>
-Cc: <stable@vger.kernel.org>
-Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
-Signed-off-by: Eric Anholt <eric@anholt.net>
-Link: https://patchwork.freedesktop.org/patch/msgid/20180430133232.32457-1-boris.brezillon@bootlin.com
-Link: https://patchwork.freedesktop.org/patch/msgid/20180430133232.32457-1-boris.brezillon@bootlin.com
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- drivers/gpu/drm/vc4/vc4_crtc.c | 46 ++++++++++++++++++++++++++++++++++++++++-
- 1 file changed, 45 insertions(+), 1 deletion(-)
-
---- a/drivers/gpu/drm/vc4/vc4_crtc.c
-+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
-@@ -735,6 +735,7 @@ static irqreturn_t vc4_crtc_irq_handler(
- struct vc4_async_flip_state {
- struct drm_crtc *crtc;
- struct drm_framebuffer *fb;
-+ struct drm_framebuffer *old_fb;
- struct drm_pending_vblank_event *event;
-
- struct vc4_seqno_cb cb;
-@@ -764,6 +765,23 @@ vc4_async_page_flip_complete(struct vc4_
-
- drm_crtc_vblank_put(crtc);
- drm_framebuffer_put(flip_state->fb);
-+
-+ /* Decrement the BO usecnt in order to keep the inc/dec calls balanced
-+ * when the planes are updated through the async update path.
-+ * FIXME: we should move to generic async-page-flip when it's
-+ * available, so that we can get rid of this hand-made cleanup_fb()
-+ * logic.
-+ */
-+ if (flip_state->old_fb) {
-+ struct drm_gem_cma_object *cma_bo;
-+ struct vc4_bo *bo;
-+
-+ cma_bo = drm_fb_cma_get_gem_obj(flip_state->old_fb, 0);
-+ bo = to_vc4_bo(&cma_bo->base);
-+ vc4_bo_dec_usecnt(bo);
-+ drm_framebuffer_put(flip_state->old_fb);
-+ }
-+
- kfree(flip_state);
-
- up(&vc4->async_modeset);
-@@ -788,9 +806,22 @@ static int vc4_async_page_flip(struct dr
- struct drm_gem_cma_object *cma_bo = drm_fb_cma_get_gem_obj(fb, 0);
- struct vc4_bo *bo = to_vc4_bo(&cma_bo->base);
-
-+ /* Increment the BO usecnt here, so that we never end up with an
-+ * unbalanced number of vc4_bo_{dec,inc}_usecnt() calls when the
-+ * plane is later updated through the non-async path.
-+ * FIXME: we should move to generic async-page-flip when it's
-+ * available, so that we can get rid of this hand-made prepare_fb()
-+ * logic.
-+ */
-+ ret = vc4_bo_inc_usecnt(bo);
-+ if (ret)
-+ return ret;
-+
- flip_state = kzalloc(sizeof(*flip_state), GFP_KERNEL);
-- if (!flip_state)
-+ if (!flip_state) {
-+ vc4_bo_dec_usecnt(bo);
- return -ENOMEM;
-+ }
-
- drm_framebuffer_get(fb);
- flip_state->fb = fb;
-@@ -801,10 +832,23 @@ static int vc4_async_page_flip(struct dr
- ret = down_interruptible(&vc4->async_modeset);
- if (ret) {
- drm_framebuffer_put(fb);
-+ vc4_bo_dec_usecnt(bo);
- kfree(flip_state);
- return ret;
- }
-
-+ /* Save the current FB before it's replaced by the new one in
-+ * drm_atomic_set_fb_for_plane(). We'll need the old FB in
-+ * vc4_async_page_flip_complete() to decrement the BO usecnt and keep
-+ * it consistent.
-+ * FIXME: we should move to generic async-page-flip when it's
-+ * available, so that we can get rid of this hand-made cleanup_fb()
-+ * logic.
-+ */
-+ flip_state->old_fb = plane->state->fb;
-+ if (flip_state->old_fb)
-+ drm_framebuffer_get(flip_state->old_fb);
-+
- WARN_ON(drm_crtc_vblank_get(crtc) != 0);
-
- /* Immediately update the plane's legacy fb pointer, so that later
projects / thirdparty / kernel / stable-queue.git / commitdiff
