drm/i915: Add pipe update trace points

Add trace points for observing the atomic pipe update mechanism.

v2: Rebased due to earlier changes
v3: Pass intel_crtc instead of drm_crtc (Daniel)
v4: Pass frame counter from the caller to evaded/end since
    the caller now always has that ready
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Sourab Gupta <sourabgupta@gmail.com>
Reviewed-by: Akash Goel <akash.goels@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_trace.h

@@ -7,6 +7,7 @@
 
 #include <drm/drmP.h>
 #include "i915_drv.h"
+#include "intel_drv.h"
 #include "intel_ringbuffer.h"
 
 #undef TRACE_SYSTEM
@@ -14,6 +15,80 @@
 #define TRACE_SYSTEM_STRING __stringify(TRACE_SYSTEM)
 #define TRACE_INCLUDE_FILE i915_trace
 
+/* pipe updates */
+
+TRACE_EVENT(i915_pipe_update_start,
+	    TP_PROTO(struct intel_crtc *crtc, u32 min, u32 max),
+	    TP_ARGS(crtc, min, max),
+
+	    TP_STRUCT__entry(
+			     __field(enum pipe, pipe)
+			     __field(u32, frame)
+			     __field(u32, scanline)
+			     __field(u32, min)
+			     __field(u32, max)
+			     ),
+
+	    TP_fast_assign(
+			   __entry->pipe = crtc->pipe;
+			   __entry->frame = crtc->base.dev->driver->get_vblank_counter(crtc->base.dev,
+										       crtc->pipe);
+			   __entry->scanline = intel_get_crtc_scanline(crtc);
+			   __entry->min = min;
+			   __entry->max = max;
+			   ),
+
+	    TP_printk("pipe %c, frame=%u, scanline=%u, min=%u, max=%u",
+		      pipe_name(__entry->pipe), __entry->frame,
+		       __entry->scanline, __entry->min, __entry->max)
+);
+
+TRACE_EVENT(i915_pipe_update_vblank_evaded,
+	    TP_PROTO(struct intel_crtc *crtc, u32 min, u32 max, u32 frame),
+	    TP_ARGS(crtc, min, max, frame),
+
+	    TP_STRUCT__entry(
+			     __field(enum pipe, pipe)
+			     __field(u32, frame)
+			     __field(u32, scanline)
+			     __field(u32, min)
+			     __field(u32, max)
+			     ),
+
+	    TP_fast_assign(
+			   __entry->pipe = crtc->pipe;
+			   __entry->frame = frame;
+			   __entry->scanline = intel_get_crtc_scanline(crtc);
+			   __entry->min = min;
+			   __entry->max = max;
+			   ),
+
+	    TP_printk("pipe %c, frame=%u, scanline=%u, min=%u, max=%u",
+		      pipe_name(__entry->pipe), __entry->frame,
+		       __entry->scanline, __entry->min, __entry->max)
+);
+
+TRACE_EVENT(i915_pipe_update_end,
+	    TP_PROTO(struct intel_crtc *crtc, u32 frame),
+	    TP_ARGS(crtc, frame),
+
+	    TP_STRUCT__entry(
+			     __field(enum pipe, pipe)
+			     __field(u32, frame)
+			     __field(u32, scanline)
+			     ),
+
+	    TP_fast_assign(
+			   __entry->pipe = crtc->pipe;
+			   __entry->frame = frame;
+			   __entry->scanline = intel_get_crtc_scanline(crtc);
+			   ),
+
+	    TP_printk("pipe %c, frame=%u, scanline=%u",
+		      pipe_name(__entry->pipe), __entry->frame,
+		      __entry->scanline)
+);
+
 /* object tracking */
 
 TRACE_EVENT(i915_gem_object_create,

drivers/gpu/drm/i915/intel_sprite.c

@@ -73,6 +73,8 @@ static bool intel_pipe_update_start(struct intel_crtc *crtc, uint32_t *start_vbl
 
 	local_irq_disable();
 
+	trace_i915_pipe_update_start(crtc, min, max);
+
 	for (;;) {
 		/*
 		 * prepare_to_wait() has a memory barrier, which guarantees
@@ -104,6 +106,8 @@ static bool intel_pipe_update_start(struct intel_crtc *crtc, uint32_t *start_vbl
 
 	*start_vbl_count = dev->driver->get_vblank_counter(dev, pipe);
 
+	trace_i915_pipe_update_vblank_evaded(crtc, min, max, *start_vbl_count);
+
 	return true;
 }
 
@@ -113,6 +117,8 @@ static void intel_pipe_update_end(struct intel_crtc *crtc, u32 start_vbl_count)
 	enum pipe pipe = crtc->pipe;
 	u32 end_vbl_count = dev->driver->get_vblank_counter(dev, pipe);
 
+	trace_i915_pipe_update_end(crtc, end_vbl_count);
+
 	local_irq_enable();
 
 	if (start_vbl_count != end_vbl_count)