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authorFrediano Ziglio <fziglio@redhat.com>2015-09-24 14:25:14 +0100
committerDave Airlie <airlied@redhat.com>2015-10-07 15:33:06 +1000
commit7eb9974f3685f36f419bf9e66cfaee92849856fe (patch)
tree7cb7b20e8908eed39d645bb53f01f4a326399c52
parent60906529bec506a4bde93f04eb5e7a9dd9c42a3b (diff)
drm/qxl: avoid buffer reservation in qxl_crtc_page_flip
This avoid a dependency lock error. According to https://lwn.net/Articles/548909/ users of WW mutex API should avoid using different context. When a buffer is reserved with qxl_bo_reserve a ww_mutex_lock without context is used. However during qxl_draw_dirty_fb different locks with specific context are used. This is detected during a machine booting with a debug kernel with lock dependency checking enabled. Like many other function in this file to avoid this problem object pinning is used. Once the object is pinned is not necessary to keep the lock so it can be released avoiding the locking problem. Signed-off-by: Frediano Ziglio <fziglio@redhat.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
-rw-r--r--drivers/gpu/drm/qxl/qxl_display.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 4649bd2ed340..183aea1abebc 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -244,6 +244,10 @@ static int qxl_crtc_page_flip(struct drm_crtc *crtc,
ret = qxl_bo_reserve(bo, false);
if (ret)
return ret;
+ ret = qxl_bo_pin(bo, bo->type, NULL);
+ qxl_bo_unreserve(bo);
+ if (ret)
+ return ret;
qxl_draw_dirty_fb(qdev, qfb_src, bo, 0, 0,
&norect, one_clip_rect, inc);
@@ -257,7 +261,11 @@ static int qxl_crtc_page_flip(struct drm_crtc *crtc,
}
drm_vblank_put(dev, qcrtc->index);
- qxl_bo_unreserve(bo);
+ ret = qxl_bo_reserve(bo, false);
+ if (!ret) {
+ qxl_bo_unpin(bo);
+ qxl_bo_unreserve(bo);
+ }
return 0;
}