On Broadwell GT3 we have 2 Video Command Streamers (VCS), but userspace
has no control when using VCS1 or VCS2. This patch introduces a mechanism
to avoid the default ping-pong mode and use one specific ring through
execution flag.
Signed-off-by: Zhipeng Gong <zhipeng.gong@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 19 +++++++++++++++++--
include/uapi/drm/i915_drm.h | 8 +++++++-
2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 60998fc..f9ed8e0 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1279,8 +1279,23 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
else if ((args->flags & I915_EXEC_RING_MASK) == I915_EXEC_BSD) {
if (HAS_BSD2(dev)) {
int ring_id;
- ring_id = gen8_dispatch_bsd_ring(dev, file);
- ring = &dev_priv->ring[ring_id];
+
+ switch (args->flags & I915_EXEC_BSD_MASK) {
+ case I915_EXEC_BSD_DEFAULT:
+ ring_id = gen8_dispatch_bsd_ring(dev, file);
+ ring = &dev_priv->ring[ring_id];
+ break;
+ case I915_EXEC_BSD_RING1:
+ ring = &dev_priv->ring[VCS];
+ break;
+ case I915_EXEC_BSD_RING2:
+ ring = &dev_priv->ring[VCS2];
+ break;
+ default:
+ DRM_DEBUG("execbuf with unknown bsd ring: %d\n",
+ (int)(args->flags & I915_EXEC_BSD_MASK));
+ return -EINVAL;
+ }
} else
ring = &dev_priv->ring[VCS];
} else
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index ff57f07..421420a 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -736,7 +736,13 @@ struct drm_i915_gem_execbuffer2 {
*/
#define I915_EXEC_HANDLE_LUT (1<<12)
-#define __I915_EXEC_UNKNOWN_FLAGS -(I915_EXEC_HANDLE_LUT<<1)
+/** Used for switching BSD rings on the platforms with two BSD rings */
+#define I915_EXEC_BSD_MASK (3<<13)
+#define I915_EXEC_BSD_DEFAULT (0<<13) /* default ping-pong mode */
+#define I915_EXEC_BSD_RING1 (1<<13)
+#define I915_EXEC_BSD_RING2 (2<<13)
+
+#define __I915_EXEC_UNKNOWN_FLAGS -(1<<15)
#define I915_EXEC_CONTEXT_ID_MASK (0xffffffff)
#define i915_execbuffer2_set_context_id(eb2, context) \
--
2.0.3
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