Re: [PATCH v2 12/13] drm/i915/dsb: Add tracepoints for DSB commit

["Borah, Chaitanya Kumar" <chaitanya.kumar.borah@intel.com>]

On 9/9/2026 9:47 PM, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Currently DSB based commits don't leave any breadcrumbs via
> tracepoints. Add new intel_dsb_commit and intel_dsb_done
> tracepoints that at least indicates when the DSB does something.
> 
> We might want to improve this later somehow to have a slightly
> better idea what the DSB might end up doing. But at least this
> now shows that *something* is happening on the hardware.
> 

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


> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>   .../drm/i915/display/intel_display_trace.h    | 51 +++++++++++++++++++
>   drivers/gpu/drm/i915/display/intel_dsb.c      |  5 ++
>   2 files changed, 56 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h b/drivers/gpu/drm/i915/display/intel_display_trace.h
> index 504d105935bc..06cf662931fe 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_trace.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_trace.h
> @@ -22,6 +22,7 @@
>   #include "intel_display_core.h"
>   #include "intel_display_limits.h"
>   #include "intel_display_types.h"
> +#include "intel_dsb.h"
>   #include "intel_vblank.h"
>   
>   #define __dev_name_display(display) dev_name((display)->drm->dev)
> @@ -681,6 +682,56 @@ TRACE_EVENT(intel_fbc_nuke,
>   		      __entry->frame, __entry->scanline)
>   );
>   
> +TRACE_EVENT(intel_dsb_commit,
> +	    TP_PROTO(struct intel_crtc *crtc, enum intel_dsb_id dsb_id),
> +	    TP_ARGS(crtc, dsb_id),
> +
> +	    TP_STRUCT__entry(
> +			     __string(dev, __dev_name_kms(crtc))
> +			     __field(char, pipe_name)
> +			     __field(u32, dsb_id)
> +			     __field(u32, frame)
> +			     __field(u32, scanline)
> +			     ),
> +
> +	    TP_fast_assign(
> +			   __assign_str(dev);
> +			   __entry->pipe_name = pipe_name(crtc->pipe);
> +			   __entry->dsb_id = dsb_id;
> +			   __entry->frame = intel_crtc_get_vblank_counter(crtc);
> +			   __entry->scanline = intel_get_crtc_scanline(crtc);
> +			   ),
> +
> +	    TP_printk("dev %s, pipe %c, DSB %d, frame=%u, scanline=%u",
> +		      __get_str(dev), __entry->pipe_name, __entry->dsb_id,
> +		      __entry->frame, __entry->scanline)
> +);
> +
> +TRACE_EVENT(intel_dsb_done,
> +	    TP_PROTO(struct intel_crtc *crtc, enum intel_dsb_id dsb_id),
> +	    TP_ARGS(crtc, dsb_id),
> +
> +	    TP_STRUCT__entry(
> +			     __string(dev, __dev_name_kms(crtc))
> +			     __field(char, pipe_name)
> +			     __field(u32, dsb_id)
> +			     __field(u32, frame)
> +			     __field(u32, scanline)
> +			     ),
> +
> +	    TP_fast_assign(
> +			   __assign_str(dev);
> +			   __entry->pipe_name = pipe_name(crtc->pipe);
> +			   __entry->dsb_id = dsb_id;
> +			   __entry->frame = intel_crtc_get_vblank_counter(crtc);
> +			   __entry->scanline = intel_get_crtc_scanline(crtc);
> +			   ),
> +
> +	    TP_printk("dev %s, pipe %c, DSB %d, frame=%u, scanline=%u",
> +		      __get_str(dev), __entry->pipe_name, __entry->dsb_id,
> +		      __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_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
> index 8e01e1eed291..299d778520a2 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -14,6 +14,7 @@
>   #include "intel_de.h"
>   #include "intel_display_regs.h"
>   #include "intel_display_rpm.h"
> +#include "intel_display_trace.h"
>   #include "intel_display_types.h"
>   #include "intel_dsb.h"
>   #include "intel_dsb_regs.h"
> @@ -982,6 +983,8 @@ void intel_dsb_commit(struct intel_dsb *dsb)
>   	intel_de_write_fw(display, DSB_HEAD(pipe, dsb->id),
>   			  intel_dsb_head(dsb));
>   
> +	trace_intel_dsb_commit(crtc, dsb->id);
> +
>   	intel_de_write_fw(display, DSB_TAIL(pipe, dsb->id),
>   			  intel_dsb_tail(dsb));
>   }
> @@ -1124,6 +1127,8 @@ void intel_dsb_irq_handler(struct intel_display *display,
>   		spin_lock(&display->drm->event_lock);
>   
>   		if (crtc->dsb_event) {
> +			trace_intel_dsb_done(crtc, dsb_id);
> +
>   			/*
>   			 * Update vblank counter/timestamp in case it
>   			 * hasn't been done yet for this frame.