[Intel-gfx] [PATCH 2/2] drm/i915: add more debug info for when atomic updates fail

[Ville Syrjälä]

On Thu, Sep 10, 2015 at 08:34:23AM -0700, Jesse Barnes wrote:
> I used these additional fields to track down the issue I saw on HSW.

We already have the tracepoints with the scanline information. Not sure
what extra this would give.

> 
> References: https://bugs.freedesktop.org/show_bug.cgi?id=91579
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> ---
>  drivers/gpu/drm/i915/intel_drv.h    |  2 ++
>  drivers/gpu/drm/i915/intel_sprite.c | 16 ++++++++++++----
>  2 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 46484e4..90cad50 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -565,6 +565,8 @@ struct intel_crtc {
>  
>  	unsigned start_vbl_count;
>  	ktime_t start_vbl_time;
> +	int min_vbl, max_vbl;
> +	int scanline_start;
>  
>  	struct intel_crtc_atomic_commit atomic;
>  
> diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
> index 0c2c62f..ff8c9d5 100644
> --- a/drivers/gpu/drm/i915/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/intel_sprite.c
> @@ -94,6 +94,9 @@ void intel_pipe_update_start(struct intel_crtc *crtc)
>  	min = vblank_start - usecs_to_scanlines(mode, 100);
>  	max = vblank_start - 1;
>  
> +	crtc->min_vbl = min;
> +	crtc->max_vbl = max;
> +
>  	local_irq_disable();
>  	crtc->start_vbl_count = 0;
>  
> @@ -122,8 +125,10 @@ void intel_pipe_update_start(struct intel_crtc *crtc)
>  		 * scanline_offset used to correct the DSL readout.)
>  		 */
>  		scanline = intel_get_crtc_scanline(crtc);
> -		if (scanline > 2 && (scanline < min || scanline > max))
> +		if (scanline > 2 && (scanline < min || scanline > max)) {
> +			crtc->scanline_start = scanline;
>  			break;
> +		}
>  
>  		if (timeout <= 0) {
>  			DRM_ERROR("Potential atomic update failure on pipe %c\n",
> @@ -169,10 +174,13 @@ void intel_pipe_update_end(struct intel_crtc *crtc)
>  
>  	local_irq_enable();
>  
> -	if (crtc->start_vbl_count && crtc->start_vbl_count != end_vbl_count)
> -		DRM_ERROR("Atomic update failure on pipe %c (start=%u end=%u) time %lld us\n",
> +	if (crtc->start_vbl_count && crtc->start_vbl_count != end_vbl_count) {
> +		DRM_ERROR("Atomic update failure on pipe %c (start=%u end=%u) time %lld us, min %d, max %d, scanline start %d, end %d\n",
>  			  pipe_name(pipe), crtc->start_vbl_count, end_vbl_count,
> -			  ktime_us_delta(end_vbl_time, crtc->start_vbl_time));
> +			  ktime_us_delta(end_vbl_time, crtc->start_vbl_time),
> +			  crtc->min_vbl, crtc->max_vbl, crtc->scanline_start,
> +			  intel_get_crtc_scanline(crtc));
> +	}
>  }
>  
>  static void
> -- 
> 1.9.1
> 
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-- 
Ville Syrjälä
Intel OTC