Re: [PATCH v2 13/13] drm/i915/dsb: Add tracepoints for flip queue

[Borah, Chaitanya Kumar]

On 9/9/2026 9:47 PM, Ville Syrjala wrote:

From: Ville Syrjälä <ville.syrj...@linux.intel.com>

Currently flip queue based commits don't leave any breadcrumbs
via tracepoints. Add new intel_flipq_add and intel_flipq_done
tracepoints that at least indicates when we something happens
via the flip queeu.

typo: queue

We might want to improve this later somehow to have a slightly
better idea what the flip queue might end up doing. But at least
this now shows that *something* is going on.

Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.bo...@intel.com>

Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
  .../drm/i915/display/intel_display_trace.h    | 60 +++++++++++++++++++
  drivers/gpu/drm/i915/display/intel_dmc.c      |  3 +
  drivers/gpu/drm/i915/display/intel_flipq.c    |  7 ++-
  3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h 
b/drivers/gpu/drm/i915/display/intel_display_trace.h
index 06cf662931fe..98ba7e20ca30 100644
--- a/drivers/gpu/drm/i915/display/intel_display_trace.h
+++ b/drivers/gpu/drm/i915/display/intel_display_trace.h
@@ -23,6 +23,7 @@
  #include "intel_display_limits.h"
  #include "intel_display_types.h"
  #include "intel_dsb.h"
+#include "intel_flipq.h"
  #include "intel_vblank.h"

#define __dev_name_display(display) dev_name((display)->drm->dev)

@@ -732,6 +733,65 @@ TRACE_EVENT(intel_dsb_done,
                      __entry->frame, __entry->scanline)
  );

+TRACE_EVENT(intel_flipq_add,

+           TP_PROTO(struct intel_crtc *crtc,
+                    enum intel_flipq_id flipq_id,
+                    enum intel_dsb_id dsb_id,
+                    u32 pts, u32 curr_pts),
+           TP_ARGS(crtc, flipq_id, dsb_id, pts, curr_pts),
+
+           TP_STRUCT__entry(
+                            __string(dev, __dev_name_kms(crtc))
+                            __field(char, pipe_name)
+                            __field(u32, flipq_id)
+                            __field(u32, dsb_id)
+                            __field(u32, pts)
+                            __field(u32, curr_pts)
+                            __field(u32, frame)
+                            __field(u32, scanline)
+                            ),
+
+           TP_fast_assign(
+                          __assign_str(dev);
+                          __entry->pipe_name = pipe_name(crtc->pipe);
+                          __entry->flipq_id = flipq_id;
+                          __entry->dsb_id = dsb_id;
+                          __entry->pts = pts;
+                          __entry->curr_pts = curr_pts;
+                          __entry->frame = intel_crtc_get_vblank_counter(crtc);
+                          __entry->scanline = intel_get_crtc_scanline(crtc);
+                          ),
+
+           TP_printk("dev %s, pipe %c, FQ %d, DSB %d, PTS %u, current PTS %u, 
frame=%u, scanline=%u",
+                     __get_str(dev), __entry->pipe_name,
+                     __entry->flipq_id, __entry->dsb_id,
+                     __entry->pts, __entry->curr_pts,
+                     __entry->frame, __entry->scanline)
+);
+
+TRACE_EVENT(intel_flipq_done,
+           TP_PROTO(struct intel_crtc *crtc),
+           TP_ARGS(crtc),
+
+           TP_STRUCT__entry(
+                            __string(dev, __dev_name_kms(crtc))
+                            __field(char, pipe_name)
+                            __field(u32, frame)
+                            __field(u32, scanline)
+                            ),
+
+           TP_fast_assign(
+                          __assign_str(dev);
+                          __entry->pipe_name = pipe_name(crtc->pipe);
+                          __entry->frame = intel_crtc_get_vblank_counter(crtc);
+                          __entry->scanline = intel_get_crtc_scanline(crtc);
+                          ),
+
+           TP_printk("dev %s, pipe %c, frame=%u, scanline=%u",
+                     __get_str(dev), __entry->pipe_name,
+                     __entry->frame, __entry->scanline)
+);
+
  TRACE_EVENT(intel_crtc_vblank_work_start,
            TP_PROTO(struct intel_crtc *crtc),
            TP_ARGS(crtc),
diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c 
b/drivers/gpu/drm/i915/display/intel_dmc.c
index a191eee240d9..a16560f94986 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -34,6 +34,7 @@
  #include "intel_display_power_well.h"
  #include "intel_display_regs.h"
  #include "intel_display_rpm.h"
+#include "intel_display_trace.h"
  #include "intel_display_types.h"
  #include "intel_display_utils.h"
  #include "intel_dmc.h"
@@ -1715,6 +1716,8 @@ void intel_pipedmc_irq_handler(struct intel_display 
*display, enum pipe pipe)
                        spin_lock(&display->drm->event_lock);

if (crtc->flipq_event) {

+                               trace_intel_flipq_done(crtc);
+
                                /*
                                 * Update vblank counter/timestamp in case it
                                 * hasn't been done yet for this frame.
diff --git a/drivers/gpu/drm/i915/display/intel_flipq.c 
b/drivers/gpu/drm/i915/display/intel_flipq.c
index 45788234fc83..e7cfacd8a5ef 100644
--- a/drivers/gpu/drm/i915/display/intel_flipq.c
+++ b/drivers/gpu/drm/i915/display/intel_flipq.c
@@ -11,6 +11,7 @@
  #include "intel_crtc.h"
  #include "intel_de.h"
  #include "intel_display_core.h"
+#include "intel_display_trace.h"
  #include "intel_display_types.h"
  #include "intel_display_utils.h"
  #include "intel_display_wa.h"
@@ -430,11 +431,13 @@ void intel_flipq_add(struct intel_crtc *crtc,
  {
        struct intel_display *display = to_intel_display(crtc);
        struct intel_flipq *flipq = &crtc->flipq[flipq_id];
+       unsigned int curr_pts;

if (!assert_flipq_has_room(crtc, flipq_id))

                return;

- pts += intel_de_read(display, PIPEDMC_FPQ_TS(crtc->pipe));

+       curr_pts = intel_de_read(display, PIPEDMC_FPQ_TS(crtc->pipe));
+       pts += curr_pts;

intel_flipq_preempt(crtc, true); @@ -446,6 +449,8 @@ void intel_flipq_add(struct intel_crtc *crtc,

        flipq->tail = (flipq->tail + 1) % 
intel_flipq_size_entries(flipq->flipq_id);
        intel_flipq_write_tail(crtc);

+ trace_intel_flipq_add(crtc, flipq_id, dsb_id, pts, curr_pts);

+
        intel_flipq_preempt(crtc, false);

intel_flipq_sw_dmc_wake(crtc);