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authorDaniel Vetter <daniel.vetter@ffwll.ch>2012-12-02 16:48:21 +0400
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-01-21 01:16:55 +0400
commitbfb899282f500eeb9dff2600729904aad0fd39e7 (patch)
tree817752a33cd9ddb8d789e1a4318a7fad080d9676 /drivers/gpu/drm/ast
parent29494c174dc4793ebd236aa522a2a1ed73b7180e (diff)
downloadlinux-bfb899282f500eeb9dff2600729904aad0fd39e7.tar.xz
drm: only take the crtc lock for ->cursor_set
First convert ->cursor_set to only take the crtc lock, since that seems to be the function with the least amount of state - the core ioctl function doesn't check anything which can change at runtime, so we don't have any object lifetime issues to contend. The only thing which is important is that the driver's implementation doesn't touch any state outside of that single crtc which is not yet properly protected by other locking: - ast: access the global ast->cache_kmap. Luckily we only have on crtc on this driver, so this is fine. Add a comment. - gma500: calls gma_power_begin|and and psb_gtt_pin|unpin, both which have their own locking to protect their state. Everything else is crtc-local. - i915: touches a bit of global gem state, all protected by the One Lock to Rule Them All (dev->struct_mutex). - nouveau: Pre-nv50 is all nice, nv50+ uses the evo channels to queue up all display changes. And some of these channels are device global. But this is fine now since the previous patch introduced an evo channel mutex. - radeon: Uses some indirect register access for cursor updates, but with the previous patches to protect these indirect 2-register access patterns with a spinlock, this should be fine now, too. - vmwgfx: I have no idea how that works - update_cursor_position doesn't take any per-crtc argument and I haven't figured out any other place where this could be set in some form of a side-channel. But vmwgfx definitely has more than one crtc (or at least can register more than one), so I have no idea how this is supposed to not fail with the current code already. Hence take the easy way out and simply acquire all locks (which requires dropping the crtc lock the core acquired for us). That way it's not worse off for consistency than the old code. Reviewed-by: Rob Clark <rob@ti.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/ast')
-rw-r--r--drivers/gpu/drm/ast/ast_drv.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index 5ccf984f063a..528429252f0f 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -98,6 +98,8 @@ struct ast_private {
struct drm_gem_object *cursor_cache;
uint64_t cursor_cache_gpu_addr;
+ /* Acces to this cache is protected by the crtc->mutex of the only crtc
+ * we have. */
struct ttm_bo_kmap_obj cache_kmap;
int next_cursor;
};