Re: [PATCH 3/6] drm/i915/reset: Move pending_fb_pin handling to i915

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 09 Apr 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Only i915 uses the pending_fb_pin counter to potentially whack
> the GPU harder if the display gets nuked during a GPU reset.
> Move the atomic counter into the i915 specific bits of code, so
> that we don't need to worry about on the display side.
>
> For some reason the overlay code kept the pending_fb_pin counter
> elevated for longer than just for the pin, but from now on it'll
> just cover the actual pinning part.
>
> Cc: Simona Vetter <simona.vetter@ffwll.ch>
> Cc: Christian König <christian.koenig@amd.com>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Jouni Högander <jouni.hogander@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Yay, this is nice!

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  .../gpu/drm/i915/display/intel_display_core.h |  1 -
>  .../drm/i915/display/intel_display_reset.c    |  9 +--------
>  .../drm/i915/display/intel_display_reset.h    |  5 +----
>  drivers/gpu/drm/i915/display/intel_overlay.c  | 10 ++--------
>  drivers/gpu/drm/i915/gt/intel_reset.c         | 19 ++++++++++---------
>  drivers/gpu/drm/i915/i915_dpt.c               |  5 ++---
>  drivers/gpu/drm/i915/i915_drv.h               |  2 ++
>  drivers/gpu/drm/i915/i915_fb_pin.c            |  9 ++++-----
>  drivers/gpu/drm/i915/i915_overlay.c           |  6 ++++++
>  9 files changed, 28 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h
> index d708d322aa85..9e77003addd0 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_core.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_core.h
> @@ -561,7 +561,6 @@ struct intel_display {
>  		struct drm_atomic_state *modeset_state;
>  		struct drm_modeset_acquire_ctx reset_ctx;
>  		/* modeset stuck tracking for reset */
> -		atomic_t pending_fb_pin;
>  		u32 saveDSPARB;
>  		u32 saveSWF0[16];
>  		u32 saveSWF1[16];
> diff --git a/drivers/gpu/drm/i915/display/intel_display_reset.c b/drivers/gpu/drm/i915/display/intel_display_reset.c
> index 137a2a33c8b0..ca15dc18ef0f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_reset.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_reset.c
> @@ -27,19 +27,12 @@ bool intel_display_reset_test(struct intel_display *display)
>  		display->params.force_reset_modeset_test;
>  }
>  
> -void intel_display_reset_prepare(struct intel_display *display,
> -				 modeset_stuck_fn modeset_stuck, void *context)
> +void intel_display_reset_prepare(struct intel_display *display)
>  {
>  	struct drm_modeset_acquire_ctx *ctx = &display->restore.reset_ctx;
>  	struct drm_atomic_state *state;
>  	int ret;
>  
> -	if (atomic_read(&display->restore.pending_fb_pin)) {
> -		drm_dbg_kms(display->drm,
> -			    "Modeset potentially stuck, unbreaking through wedging\n");
> -		modeset_stuck(context);
> -	}
> -
>  	/*
>  	 * Need mode_config.mutex so that we don't
>  	 * trample ongoing ->detect() and whatnot.
> diff --git a/drivers/gpu/drm/i915/display/intel_display_reset.h b/drivers/gpu/drm/i915/display/intel_display_reset.h
> index e0f15e757728..a8aa7729d33f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_reset.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_reset.h
> @@ -10,12 +10,9 @@
>  
>  struct intel_display;
>  
> -typedef void modeset_stuck_fn(void *context);
> -
>  bool intel_display_reset_supported(struct intel_display *display);
>  bool intel_display_reset_test(struct intel_display *display);
> -void intel_display_reset_prepare(struct intel_display *display,
> -				 modeset_stuck_fn modeset_stuck, void *context);
> +void intel_display_reset_prepare(struct intel_display *display);
>  void intel_display_reset_finish(struct intel_display *display, bool test_only);
>  
>  #endif /* __INTEL_RESET_H__ */
> diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
> index 12a325ceae6f..a809aa2950ac 100644
> --- a/drivers/gpu/drm/i915/display/intel_overlay.c
> +++ b/drivers/gpu/drm/i915/display/intel_overlay.c
> @@ -481,13 +481,9 @@ static int intel_overlay_do_put_image(struct intel_overlay *overlay,
>  	if (ret != 0)
>  		return ret;
>  
> -	atomic_inc(&display->restore.pending_fb_pin);
> -
>  	vma = intel_parent_overlay_pin_fb(display, obj, &offset);
> -	if (IS_ERR(vma)) {
> -		ret = PTR_ERR(vma);
> -		goto out_pin_section;
> -	}
> +	if (IS_ERR(vma))
> +		return PTR_ERR(vma);
>  
>  	if (!intel_parent_overlay_is_active(display)) {
>  		const struct intel_crtc_state *crtc_state =
> @@ -571,8 +567,6 @@ static int intel_overlay_do_put_image(struct intel_overlay *overlay,
>  
>  out_unpin:
>  	intel_parent_overlay_unpin_fb(display, vma);
> -out_pin_section:
> -	atomic_dec(&display->restore.pending_fb_pin);
>  
>  	return ret;
>  }
> diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
> index ffd11767874f..a1e6aaca8c9b 100644
> --- a/drivers/gpu/drm/i915/gt/intel_reset.c
> +++ b/drivers/gpu/drm/i915/gt/intel_reset.c
> @@ -1398,11 +1398,6 @@ int intel_engine_reset(struct intel_engine_cs *engine, const char *msg)
>  	return err;
>  }
>  
> -static void display_reset_modeset_stuck(void *gt)
> -{
> -	intel_gt_set_wedged(gt);
> -}
> -
>  static void intel_gt_reset_global(struct intel_gt *gt,
>  				  u32 engine_mask,
>  				  const char *reason)
> @@ -1434,10 +1429,16 @@ static void intel_gt_reset_global(struct intel_gt *gt,
>  			intel_display_reset_test(display) ||
>  			need_display_reset;
>  
> -		if (reset_display)
> -			intel_display_reset_prepare(display,
> -						    display_reset_modeset_stuck,
> -						    gt);
> +		if (reset_display) {
> +			if (atomic_read(&i915->pending_fb_pin)) {
> +				drm_dbg_kms(&i915->drm,
> +					    "Modeset potentially stuck, unbreaking through wedging\n");
> +
> +				intel_gt_set_wedged(gt);
> +			}
> +
> +			intel_display_reset_prepare(display);
> +		}
>  
>  		intel_gt_reset(gt, engine_mask, reason);
>  
> diff --git a/drivers/gpu/drm/i915/i915_dpt.c b/drivers/gpu/drm/i915/i915_dpt.c
> index 9f47bb563c85..fcd7cced771d 100644
> --- a/drivers/gpu/drm/i915/i915_dpt.c
> +++ b/drivers/gpu/drm/i915/i915_dpt.c
> @@ -129,7 +129,6 @@ static void dpt_cleanup(struct i915_address_space *vm)
>  struct i915_vma *i915_dpt_pin_to_ggtt(struct intel_dpt *dpt, unsigned int alignment)
>  {
>  	struct drm_i915_private *i915 = dpt->vm.i915;
> -	struct intel_display *display = i915->display;
>  	struct ref_tracker *wakeref;
>  	struct i915_vma *vma;
>  	void __iomem *iomem;
> @@ -141,7 +140,7 @@ struct i915_vma *i915_dpt_pin_to_ggtt(struct intel_dpt *dpt, unsigned int alignm
>  		pin_flags |= PIN_MAPPABLE;
>  
>  	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
> -	atomic_inc(&display->restore.pending_fb_pin);
> +	atomic_inc(&i915->pending_fb_pin);
>  
>  	for_i915_gem_ww(&ww, err, true) {
>  		err = i915_gem_object_lock(dpt->obj, &ww);
> @@ -171,7 +170,7 @@ struct i915_vma *i915_dpt_pin_to_ggtt(struct intel_dpt *dpt, unsigned int alignm
>  
>  	dpt->obj->mm.dirty = true;
>  
> -	atomic_dec(&display->restore.pending_fb_pin);
> +	atomic_dec(&i915->pending_fb_pin);
>  	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
>  
>  	return err ? ERR_PTR(err) : vma;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index dafee3dcd1c5..844ed79e7211 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -315,6 +315,8 @@ struct drm_i915_private {
>  	/* The TTM device structure. */
>  	struct ttm_device bdev;
>  
> +	atomic_t pending_fb_pin;
> +
>  	I915_SELFTEST_DECLARE(struct i915_selftest_stash selftest;)
>  
>  	/*
> diff --git a/drivers/gpu/drm/i915/i915_fb_pin.c b/drivers/gpu/drm/i915/i915_fb_pin.c
> index 1018f4b7bc2c..a08a8ace681f 100644
> --- a/drivers/gpu/drm/i915/i915_fb_pin.c
> +++ b/drivers/gpu/drm/i915/i915_fb_pin.c
> @@ -29,7 +29,6 @@ intel_fb_pin_to_dpt(const struct drm_framebuffer *fb,
>  		    unsigned long *out_flags,
>  		    struct intel_dpt *dpt)
>  {
> -	struct intel_display *display = to_intel_display(fb->dev);
>  	struct drm_i915_private *i915 = to_i915(fb->dev);
>  	struct drm_gem_object *_obj = intel_fb_bo(fb);
>  	struct drm_i915_gem_object *obj = to_intel_bo(_obj);
> @@ -48,7 +47,7 @@ intel_fb_pin_to_dpt(const struct drm_framebuffer *fb,
>  	if (WARN_ON(!i915_gem_object_is_framebuffer(obj)))
>  		return ERR_PTR(-EINVAL);
>  
> -	atomic_inc(&display->restore.pending_fb_pin);
> +	atomic_inc(&i915->pending_fb_pin);
>  
>  	for_i915_gem_ww(&ww, ret, true) {
>  		ret = i915_gem_object_lock(obj, &ww);
> @@ -103,7 +102,7 @@ intel_fb_pin_to_dpt(const struct drm_framebuffer *fb,
>  
>  	i915_vma_get(vma);
>  err:
> -	atomic_dec(&display->restore.pending_fb_pin);
> +	atomic_dec(&i915->pending_fb_pin);
>  
>  	return vma;
>  }
> @@ -142,7 +141,7 @@ intel_fb_pin_to_ggtt(const struct drm_framebuffer *fb,
>  	 */
>  	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
>  
> -	atomic_inc(&display->restore.pending_fb_pin);
> +	atomic_inc(&i915->pending_fb_pin);
>  
>  	/*
>  	 * Valleyview is definitely limited to scanning out the first
> @@ -218,7 +217,7 @@ intel_fb_pin_to_ggtt(const struct drm_framebuffer *fb,
>  	if (ret)
>  		vma = ERR_PTR(ret);
>  
> -	atomic_dec(&display->restore.pending_fb_pin);
> +	atomic_dec(&i915->pending_fb_pin);
>  	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
>  	return vma;
>  }
> diff --git a/drivers/gpu/drm/i915/i915_overlay.c b/drivers/gpu/drm/i915/i915_overlay.c
> index 2d7aff51e39b..6de550a17756 100644
> --- a/drivers/gpu/drm/i915/i915_overlay.c
> +++ b/drivers/gpu/drm/i915/i915_overlay.c
> @@ -354,11 +354,14 @@ static struct i915_vma *i915_overlay_pin_fb(struct drm_device *drm,
>  					    struct drm_gem_object *obj,
>  					    u32 *offset)
>  {
> +	struct drm_i915_private *i915 = to_i915(drm);
>  	struct drm_i915_gem_object *new_bo = to_intel_bo(obj);
>  	struct i915_gem_ww_ctx ww;
>  	struct i915_vma *vma;
>  	int ret;
>  
> +	atomic_inc(&i915->pending_fb_pin);
> +
>  	i915_gem_ww_ctx_init(&ww, true);
>  retry:
>  	ret = i915_gem_object_lock(new_bo, &ww);
> @@ -373,6 +376,9 @@ static struct i915_vma *i915_overlay_pin_fb(struct drm_device *drm,
>  			goto retry;
>  	}
>  	i915_gem_ww_ctx_fini(&ww);
> +
> +	atomic_dec(&i915->pending_fb_pin);
> +
>  	if (ret)
>  		return ERR_PTR(ret);

-- 
Jani Nikula, Intel