Get rid of dt_dev_pixelpipe_t obsolete

We had `obsolete` in dt_dev_pixelpipe_t for brute-force invalidation of all pipe cachelines while not
being fully sure about piece hashes and input OpenCL cachelines not written back if changed.

Not necessary any more, **if** we would want further help for cache efficiency that would go via testing
for DT_DEV_PIPE_REMOVE and/or DT_DEV_PIPE_SYNCH

Author: jenshannoschwalm

src/develop/develop.c

@@ -2799,7 +2799,6 @@ void dt_dev_reprocess_center(dt_develop_t *dev)
   if(dev && dev->gui_attached)
   {
     dev->full.pipe->changed |= DT_DEV_PIPE_SYNCH;
-    dev->full.pipe->cache_obsolete = TRUE;
 
     // invalidate buffers and force redraw of darkroom
     dt_dev_invalidate_all(dev);
@@ -2815,7 +2814,6 @@ void dt_dev_reprocess_preview(dt_develop_t *dev)
     return;
 
   dev->preview_pipe->changed |= DT_DEV_PIPE_SYNCH;
-  dev->preview_pipe->cache_obsolete = TRUE;
 
   dt_dev_invalidate_preview(dev);
   dt_control_queue_redraw_center();

src/develop/pixelpipe_hb.c

@@ -276,7 +276,6 @@ gboolean dt_dev_pixelpipe_init_cached(dt_dev_pixelpipe_t *pipe,
   pipe->processed_height = pipe->backbuf_height = pipe->iheight = pipe->final_height = 0;
   pipe->nodes = NULL;
   pipe->backbuf_size = size;
-  pipe->cache_obsolete = FALSE;
   pipe->backbuf = NULL;
   pipe->backbuf_scale = 0.0f;
   memset(pipe->backbuf_zoom_pos, 0, sizeof(dt_dev_zoom_pos_t));
@@ -473,10 +472,6 @@ void dt_dev_pixelpipe_rebuild(dt_develop_t *dev)
   dev->preview_pipe->changed |= DT_DEV_PIPE_REMOVE;
   dev->preview2.pipe->changed |= DT_DEV_PIPE_REMOVE;
 
-  dev->full.pipe->cache_obsolete = TRUE;
-  dev->preview_pipe->cache_obsolete = TRUE;
-  dev->preview2.pipe->cache_obsolete = TRUE;
-
   // invalidate buffers and force redraw of darkroom
   dt_dev_invalidate_all(dev);
 }
@@ -3107,11 +3102,6 @@ gboolean dt_dev_pixelpipe_process(dt_dev_pixelpipe_t *pipe,
 // re-entry point: in case of late opencl errors we start all over
 // again with opencl-support disabled
 restart:
-
-  // check if we should obsolete caches
-  if(pipe->cache_obsolete) dt_dev_pixelpipe_cache_flush(pipe);
-  pipe->cache_obsolete = FALSE;
-
   // mask display off as a starting point
   pipe->mask_display = DT_DEV_PIXELPIPE_DISPLAY_NONE;
   // and blendif active

src/develop/pixelpipe_hb.h

@@ -165,8 +165,6 @@ typedef struct dt_dev_pixelpipe_t
 {
   // store history/zoom caches
   dt_dev_pixelpipe_cache_t cache;
-  // set to TRUE in order to obsolete old cache entries on next pixelpipe run
-  gboolean cache_obsolete;
   uint64_t runs; // used only for pixelpipe cache statistics
   // input buffer
   float *input;

src/gui/color_picker_proxy.c

@@ -300,7 +300,6 @@ static void _iop_color_picker_pickerdata_ready_callback(gpointer instance,
   // will set the work_profile if needed.
   // FIXME: is this overdoing it? see #14812
   pipe->changed |= DT_DEV_PIPE_REMOVE;
-  pipe->cache_obsolete = TRUE;
 
   // iops only need new picker data if the pointer has moved
   if(_record_point_area(picker))

src/views/darkroom.c

@@ -4661,7 +4661,6 @@ static gboolean _second_window_configure_callback(GtkWidget *da,
     // pipe needs to be reconstructed
     dev->preview2.pipe->status = DT_DEV_PIXELPIPE_DIRTY;
     dev->preview2.pipe->changed |= DT_DEV_PIPE_REMOVE;
-    dev->preview2.pipe->cache_obsolete = TRUE;
 
     // If we have a pinned image, update its viewport dimensions too
     dt_develop_t *pinned_dev = dev->preview2_pinned ? dev->preview2_pinned_dev : NULL;
@@ -4674,7 +4673,6 @@ static gboolean _second_window_configure_callback(GtkWidget *da,
       pinned_port->orig_height = event->height;
       pinned_port->pipe->status = DT_DEV_PIXELPIPE_DIRTY;
       pinned_port->pipe->changed |= DT_DEV_PIPE_REMOVE;
-      pinned_port->pipe->cache_obsolete = TRUE;
     }
   }