diff --git a/src/common/darktable.c b/src/common/darktable.c
index 85dc9cbbbb09..a24a7d8d99de 100644
--- a/src/common/darktable.c
+++ b/src/common/darktable.c
@@ -513,6 +513,20 @@ void dt_dump_pipe_pfm(
   dt_dump_pfm_file(pipe, data, width, height, bpp, mod, "[dt_dump_pipe_pfm]", input, !input, TRUE);
 }
 
+static int32_t _detect_opencl_job_run(dt_job_t *job)
+{
+  darktable.opencl = (dt_opencl_t *)calloc(1, sizeof(dt_opencl_t));
+  dt_opencl_init(darktable.opencl, GPOINTER_TO_INT(dt_control_job_get_params(job)), TRUE);
+  return 0;
+}
+
+static dt_job_t *_detect_opencl_job_create(gboolean exclude_opencl)
+{
+  dt_job_t *job = dt_control_job_create(&_detect_opencl_job_run, "detect opencl devices");
+  if(!job) return NULL;
+  dt_control_job_set_params(job, GINT_TO_POINTER(exclude_opencl), NULL);
+  return job;
+}
 
 int dt_init(int argc, char *argv[], const gboolean init_gui, const gboolean load_data, lua_State *L)
 {
@@ -1354,10 +1368,11 @@ int dt_init(int argc, char *argv[], const gboolean init_gui, const gboolean load
 #endif
 
   darktable.opencl = (dt_opencl_t *)calloc(1, sizeof(dt_opencl_t));
-  dt_opencl_init(darktable.opencl, exclude_opencl, print_statistics);
-#ifdef HAVE_OPENCL
-  dt_opencl_update_settings();
-#endif
+  if(init_gui)
+    dt_control_add_job(darktable.control, DT_JOB_QUEUE_SYSTEM_BG,
+                       _detect_opencl_job_create(exclude_opencl));
+  else
+    dt_opencl_init(darktable.opencl, exclude_opencl, print_statistics);
 
   darktable.points = (dt_points_t *)calloc(1, sizeof(dt_points_t));
   dt_points_init(darktable.points, dt_get_num_threads());
diff --git a/src/common/opencl.c b/src/common/opencl.c
index d90104946368..5fe3dea874c5 100644
--- a/src/common/opencl.c
+++ b/src/common/opencl.c
@@ -64,6 +64,7 @@ static float _opencl_benchmark_cpu(const size_t width,
 
 static gboolean _opencl_load_program(const int dev,
                                      const int prog,
+                                     const char *programname,
                                      const char *filename,
                                      const char *binname,
                                      const char *cachedir,
@@ -1074,7 +1075,7 @@ static gboolean _opencl_device_init(dt_opencl_t *cl,
                "[dt_opencl_device_init] testing program `%s' ..\n", programname);
       int loaded_cached;
       char md5sum[33];
-      if(_opencl_load_program(dev, prog, filename, binname, cachedir,
+      if(_opencl_load_program(dev, prog, programname, filename, binname, cachedir,
                               md5sum, includemd5, &loaded_cached)
          && _opencl_build_program(dev, prog, binname, cachedir, md5sum, loaded_cached))
       {
@@ -1543,7 +1544,7 @@ void dt_opencl_init(
     free(locale);
   }
 
-  return;
+  dt_opencl_update_settings();
 }
 
 void dt_opencl_cleanup(dt_opencl_t *cl)
@@ -2297,6 +2298,7 @@ void dt_opencl_md5sum(const char **files, char **md5sums)
 static gboolean _opencl_load_program(
         const int dev,
         const int prog,
+        const char *programname,
         const char *filename,
         const char *binname,
         const char *cachedir,
@@ -2463,6 +2465,8 @@ static gboolean _opencl_load_program(
              "[opencl_load_program] could not load cached binary program,"
              " trying to compile source\n");
 
+    dt_control_log(_("building OpenCL program %s for %s"),
+                  programname, cl->dev[dev].fullname);
     cl->dev[dev].program[prog] = (cl->dlocl->symbols->dt_clCreateProgramWithSource)(
         cl->dev[dev].context, 1, (const char **)&file, &filesize, &err);
     free(file);
@@ -2660,51 +2664,56 @@ static gboolean _opencl_build_program(const int dev,
 int dt_opencl_create_kernel(const int prog, const char *name)
 {
   dt_opencl_t *cl = darktable.opencl;
-  if(!cl->inited) return -1;
-  if(prog < 0 || prog >= DT_OPENCL_MAX_PROGRAMS) return -1;
+
+  static int k = 0;
+  cl->name_saved[k] = name;
+  cl->program_saved[k] = prog;
+
+  if(k >= DT_OPENCL_MAX_KERNELS)
+  {
+    dt_print(DT_DEBUG_OPENCL,
+              "[opencl_create_kernel] too many kernels! can't create kernel `%s'\n",
+              name);
+    return -1;
+  }
+  return k++;
+}
+
+
+static gboolean _check_kernel(const int dev, const int kernel)
+{
+  dt_opencl_t *cl = darktable.opencl;
+
+  if(!cl->inited || dev < 0) return FALSE;
+  if(kernel < 0 || kernel >= DT_OPENCL_MAX_KERNELS) return FALSE;
+  
+  if(cl->dev[dev].kernel_used[kernel]) return TRUE;
+
+  const int prog = cl->program_saved[kernel];
+  if(prog < 0 || prog >= DT_OPENCL_MAX_PROGRAMS) return FALSE;
   dt_pthread_mutex_lock(&cl->lock);
-  int k = 0;
-  for(int dev = 0; dev < cl->num_devs; dev++)
+
+  cl_int err;
+  if(!cl->dev[dev].kernel_used[kernel]
+     && cl->name_saved[kernel])
   {
-    cl_int err;
-    for(; k < DT_OPENCL_MAX_KERNELS; k++)
-      if(!cl->dev[dev].kernel_used[k])
-      {
-        cl->dev[dev].kernel_used[k] = 1;
-        cl->dev[dev].kernel[k] =
-          (cl->dlocl->symbols->dt_clCreateKernel)
-            (cl->dev[dev].program[prog], name, &err);
-        if(err != CL_SUCCESS)
-        {
-          dt_print(DT_DEBUG_OPENCL,
-                   "[opencl_create_kernel] could not create kernel `%s'! (%s)\n",
-                   name, cl_errstr(err));
-          cl->dev[dev].kernel_used[k] = 0;
-          goto error;
-        }
-        else
-          break;
-      }
-    if(k < DT_OPENCL_MAX_KERNELS)
-    {
-      dt_print(DT_DEBUG_OPENCL | DT_DEBUG_VERBOSE,
-               "[opencl_create_kernel] successfully loaded kernel `%s' (%d)"
-               " for device %d\n",
-               name, k, dev);
-    }
-    else
+    cl->dev[dev].kernel_used[kernel] = 1;
+    cl->dev[dev].kernel[kernel] =
+      (cl->dlocl->symbols->dt_clCreateKernel)
+        (cl->dev[dev].program[prog], cl->name_saved[kernel], &err);
+    if(err != CL_SUCCESS)
     {
       dt_print(DT_DEBUG_OPENCL,
-               "[opencl_create_kernel] too many kernels! can't create kernel `%s'\n",
-               name);
-      goto error;
+                "[opencl_create_kernel] could not create kernel `%s'! (%s)\n",
+                cl->name_saved[kernel], cl_errstr(err));
+      cl->dev[dev].kernel_used[kernel] = 0;
+      cl->name_saved[kernel] = NULL; // don't try again
+      dt_pthread_mutex_unlock(&cl->lock);
+      return FALSE;
     }
   }
   dt_pthread_mutex_unlock(&cl->lock);
-  return k;
-error:
-  dt_pthread_mutex_unlock(&cl->lock);
-  return -1;
+  return TRUE;
 }
 
 void dt_opencl_free_kernel(const int kernel)
@@ -2763,10 +2772,9 @@ int dt_opencl_get_kernel_work_group_size(
         const int kernel,
         size_t *kernelworkgroupsize)
 {
-  dt_opencl_t *cl = darktable.opencl;
-  if(!cl->inited || dev < 0) return -1;
-  if(kernel < 0 || kernel >= DT_OPENCL_MAX_KERNELS) return -1;
+  if(!_check_kernel(dev, kernel)) return -1;
 
+  dt_opencl_t *cl = darktable.opencl;
   return (cl->dlocl->symbols->dt_clGetKernelWorkGroupInfo)(cl->dev[dev].kernel[kernel],
                                                            cl->dev[dev].devid,
                                                            CL_KERNEL_WORK_GROUP_SIZE,
@@ -2781,9 +2789,9 @@ int dt_opencl_set_kernel_arg(
         const size_t size,
         const void *arg)
 {
+  if(!_check_kernel(dev, kernel)) return -1;
+  
   dt_opencl_t *cl = darktable.opencl;
-  if(!cl->inited || dev < 0) return -1;
-  if(kernel < 0 || kernel >= DT_OPENCL_MAX_KERNELS) return -1;
   return (cl->dlocl->symbols->dt_clSetKernelArg)
     (cl->dev[dev].kernel[kernel], num, size, arg);
 }
diff --git a/src/common/opencl.h b/src/common/opencl.h
index 5879311e907b..44db407a88ee 100644
--- a/src/common/opencl.h
+++ b/src/common/opencl.h
@@ -268,6 +268,10 @@ typedef struct dt_opencl_t
 
   // global kernels for guided filter.
   struct dt_guided_filter_cl_global_t *guided_filter;
+
+  // saved kernel info for deferred initialisation
+  int program_saved[DT_OPENCL_MAX_KERNELS];
+  const char *name_saved[DT_OPENCL_MAX_KERNELS];
 } dt_opencl_t;
 
 /** description of memory requirements of local buffer
diff --git a/src/common/variables.c b/src/common/variables.c
index 8cfd1ae0cfe8..7696760865ed 100644
--- a/src/common/variables.c
+++ b/src/common/variables.c
@@ -699,7 +699,7 @@ static char *_get_base_value(dt_variables_params_t *params, char **variable)
   else if(_has_prefix(variable, "OPENCL.ACTIVATED")
           || _has_prefix(variable, "OPENCL_ACTIVATED"))
   {
-    if(dt_opencl_is_enabled())
+    if(dt_opencl_running())
       result = g_strdup(_("yes"));
     else
       result = g_strdup(_("no"));
diff --git a/src/develop/imageop.c b/src/develop/imageop.c
index 58a86d9cf93b..c41258c0cecd 100644
--- a/src/develop/imageop.c
+++ b/src/develop/imageop.c
@@ -337,12 +337,6 @@ int dt_iop_load_module_so(void *m, const char *libname, const char *module_name)
   if(!module->modify_roi_in) module->modify_roi_in = _iop_modify_roi_in;
   if(!module->modify_roi_out) module->modify_roi_out = _iop_modify_roi_out;
 
-  #ifdef HAVE_OPENCL
-  if(!module->process_tiling_cl)
-    module->process_tiling_cl = darktable.opencl->inited ? default_process_tiling_cl : NULL;
-  if(!darktable.opencl->inited) module->process_cl = NULL;
-  #endif // HAVE_OPENCL
-
   module->process_plain = module->process;
   module->process = default_process;
 
diff --git a/src/iop/iop_api.h b/src/iop/iop_api.h
index 0a13743a806f..92f665ca8e17 100644
--- a/src/iop/iop_api.h
+++ b/src/iop/iop_api.h
@@ -86,28 +86,28 @@ DEFAULT(int, operation_tags_filter, void);
 
 /** what do the iop want as an input? */
 DEFAULT(void, input_format, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                             struct dt_dev_pixelpipe_iop_t *piece, struct dt_iop_buffer_dsc_t *dsc);
+                            struct dt_dev_pixelpipe_iop_t *piece, struct dt_iop_buffer_dsc_t *dsc);
 /** what will it output? */
 DEFAULT(void, output_format, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                              struct dt_dev_pixelpipe_iop_t *piece, struct dt_iop_buffer_dsc_t *dsc);
+                             struct dt_dev_pixelpipe_iop_t *piece, struct dt_iop_buffer_dsc_t *dsc);
 
 /** what default colorspace this iop use? */
 REQUIRED(dt_iop_colorspace_type_t, default_colorspace, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                                  struct dt_dev_pixelpipe_iop_t *piece);
+                                   struct dt_dev_pixelpipe_iop_t *piece);
 /** what input colorspace it expects? */
 DEFAULT(dt_iop_colorspace_type_t, input_colorspace, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                                struct dt_dev_pixelpipe_iop_t *piece);
+                                  struct dt_dev_pixelpipe_iop_t *piece);
 /** what will it output? */
 DEFAULT(dt_iop_colorspace_type_t, output_colorspace, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                                 struct dt_dev_pixelpipe_iop_t *piece);
+                                  struct dt_dev_pixelpipe_iop_t *piece);
 /** what colorspace the blend module operates with? */
 DEFAULT(dt_iop_colorspace_type_t, blend_colorspace, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                                struct dt_dev_pixelpipe_iop_t *piece);
+                                  struct dt_dev_pixelpipe_iop_t *piece);
 
 /** report back info for tiling: memory usage and overlap. Memory usage: factor * input_size + overhead */
 DEFAULT(void, tiling_callback, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece,
-                                const struct dt_iop_roi_t *roi_in, const struct dt_iop_roi_t *roi_out,
-                                struct dt_develop_tiling_t *tiling);
+                               const struct dt_iop_roi_t *roi_in, const struct dt_iop_roi_t *roi_out,
+                               struct dt_develop_tiling_t *tiling);
 
 /** callback methods for gui. */
 /** synch gtk interface with gui params, if necessary. */
@@ -146,12 +146,12 @@ DEFAULT(void, cleanup, struct dt_iop_module_t *self);
 
 /** this inits the piece of the pipe, allocing piece->data as necessary. */
 DEFAULT(void, init_pipe, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                          struct dt_dev_pixelpipe_iop_t *piece);
+                         struct dt_dev_pixelpipe_iop_t *piece);
 /** this resets the params to factory defaults. used at the beginning of each history synch. */
 /** this commits (a mutex will be locked to synch pipe/gui) the given history params to the pixelpipe piece.
  */
 DEFAULT(void, commit_params, struct dt_iop_module_t *self, dt_iop_params_t *params, struct dt_dev_pixelpipe_t *pipe,
-                              struct dt_dev_pixelpipe_iop_t *piece);
+                             struct dt_dev_pixelpipe_iop_t *piece);
 /** this is the chance to update default parameters, after the full raw is loaded. */
 OPTIONAL(void, reload_defaults, struct dt_iop_module_t *self);
 /** called after the image has changed in darkroom */
@@ -159,7 +159,7 @@ OPTIONAL(void, change_image, struct dt_iop_module_t *self);
 
 /** this destroys all resources needed by the piece of the pixelpipe. */
 DEFAULT(void, cleanup_pipe, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_t *pipe,
-                             struct dt_dev_pixelpipe_iop_t *piece);
+                            struct dt_dev_pixelpipe_iop_t *piece);
 OPTIONAL(void, modify_roi_in, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece,
                               const struct dt_iop_roi_t *roi_out, struct dt_iop_roi_t *roi_in);
 OPTIONAL(void, modify_roi_out, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece,
@@ -185,8 +185,8 @@ REQUIRED(void, process, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_io
                         const struct dt_iop_roi_t *const roi_out);
 /** a tiling variant of process(). */
 DEFAULT(void, process_tiling, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece, const void *const i,
-                               void *const o, const struct dt_iop_roi_t *const roi_in,
-                               const struct dt_iop_roi_t *const roi_out, const int bpp);
+                              void *const o, const struct dt_iop_roi_t *const roi_in,
+                              const struct dt_iop_roi_t *const roi_out, const int bpp);
 
 #ifdef HAVE_OPENCL
 /** the opencl equivalent of process(). */
@@ -194,9 +194,9 @@ OPTIONAL(int, process_cl, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_
                           cl_mem dev_out, const struct dt_iop_roi_t *const roi_in,
                           const struct dt_iop_roi_t *const roi_out);
 /** a tiling variant of process_cl(). */
-OPTIONAL(int, process_tiling_cl, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece, const void *const i,
-                                 void *const o, const struct dt_iop_roi_t *const roi_in,
-                                 const struct dt_iop_roi_t *const roi_out, const int bpp);
+DEFAULT(int, process_tiling_cl, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece, const void *const i,
+                                void *const o, const struct dt_iop_roi_t *const roi_in,
+                                const struct dt_iop_roi_t *const roi_out, const int bpp);
 #endif
 
 /** this functions are used for distort iop
@@ -204,10 +204,10 @@ OPTIONAL(int, process_tiling_cl, struct dt_iop_module_t *self, struct dt_dev_pix
  * size is 2*points_count */
 /** points before the iop is applied => point after processed */
 DEFAULT(int, distort_transform, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece, float *points,
-                                 size_t points_count);
+                                size_t points_count);
 /** reverse points after the iop is applied => point before process */
 DEFAULT(int, distort_backtransform, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece, float *points,
-                                     size_t points_count);
+                                    size_t points_count);
 
 OPTIONAL(void, distort_mask, struct dt_iop_module_t *self, struct dt_dev_pixelpipe_iop_t *piece, const float *const in,
                              float *const out, const struct dt_iop_roi_t *const roi_in, const struct dt_iop_roi_t *const roi_out);