[PATCH v3 6/8] drm: add drm_mode_atomic_commit event

[Pierre-Eric Pelloux-Prayer]

With this and the dma_fence_used_as_dependency event, a tool can draw the
relationship between the compositing draw, the atomic commit, and vblank.

An example on a 2 monitors system look like this:

gnome-shell-1638    [018] .....  2571.905124: drm_mode_atomic_commit: file=00000000245c3f0c, pid=    1165, flags=00000201, crtcs={0x1}
gnome-shell-1638    [018] .....  2571.905147: dma_fence_used_as_dependency: driver=drm_sched timeline=gfx_0.0.0 context=270 seqno=73240 reason=dma_fence_chain_init
gnome-shell-1638    [018] .....  2571.913226: drm_mode_atomic_commit: file=00000000245c3f0c, pid=    1165, flags=00000201, crtcs={0x0}
gnome-shell-1638    [018] .....  2571.913250: dma_fence_used_as_dependency: driver=drm_sched timeline=gfx_0.0.0 context=270 seqno=73241 reason=dma_fence_chain_init
    <idle>-0       [018] d.h3.  2571.915687: drm_vblank_event: crtc=1, seq=155747, time=2571916093743, high-prec=true
    <idle>-0       [018] d.h3.  2571.915968: drm_vblank_event: crtc=0, seq=153862, time=2571916377180, high-prec=true

v2: fix unchecked memory allocation

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
---
 drivers/gpu/drm/drm_atomic_uapi.c | 21 +++++++++++++++++++++
 drivers/gpu/drm/drm_trace.h       | 23 +++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 29d4940188d4..f31b5c6f870b 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -41,6 +41,7 @@
 #include <linux/file.h>
 
 #include "drm_crtc_internal.h"
+#include "drm_trace.h"
 
 /**
  * DOC: overview
@@ -1503,6 +1504,26 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 		drm_mode_object_put(obj);
 	}
 
+	if (trace_drm_mode_atomic_commit_enabled()) {
+		struct drm_crtc_state *crtc_state;
+		struct drm_crtc *crtc;
+		int *crtcs;
+		int i, num_crtcs;
+
+		crtcs = kcalloc(dev->mode_config.num_crtc, sizeof(int),
+				GFP_KERNEL);
+
+		if (crtcs) {
+			num_crtcs = 0;
+			for_each_new_crtc_in_state(state, crtc, crtc_state, i)
+				crtcs[num_crtcs++] = drm_crtc_index(crtc);
+
+			trace_drm_mode_atomic_commit(file_priv, crtcs, num_crtcs, arg->flags);
+
+			kfree(crtcs);
+		}
+	}
+
 	ret = prepare_signaling(dev, state, arg, file_priv, &fence_state,
 				&num_fences);
 	if (ret)
diff --git a/drivers/gpu/drm/drm_trace.h b/drivers/gpu/drm/drm_trace.h
index 11c6dd577e8e..63489923c289 100644
--- a/drivers/gpu/drm/drm_trace.h
+++ b/drivers/gpu/drm/drm_trace.h
@@ -66,6 +66,29 @@ TRACE_EVENT(drm_vblank_event_delivered,
 		      __entry->seq)
 );
 
+TRACE_EVENT(drm_mode_atomic_commit,
+	    TP_PROTO(struct drm_file *file, int *crtcs, int ncrtcs, uint32_t flags),
+	    TP_ARGS(file, crtcs, ncrtcs, flags),
+	    TP_STRUCT__entry(
+		    __field(struct drm_file *, file)
+		    __dynamic_array(u32, crtcs, ncrtcs)
+		    __field(uint32_t, ncrtcs)
+		    __field(uint32_t, flags)
+		    ),
+	    TP_fast_assign(
+		    unsigned int i;
+
+		    __entry->file = file;
+		    for (i = 0; i < ncrtcs; i++)
+			((u32 *)__get_dynamic_array(crtcs))[i] = crtcs[i];
+		    __entry->ncrtcs = ncrtcs;
+		    __entry->flags = flags;
+		    ),
+	    TP_printk("file=%p, pid=%8d, flags=%08x, crtcs=%s", __entry->file,
+		      pid_nr(__entry->file->pid), __entry->flags,
+		      __print_array(__get_dynamic_array(crtcs), __entry->ncrtcs, 4))
+);
+
 #endif /* _DRM_TRACE_H_ */
 
 /* This part must be outside protection */
-- 
2.40.1