dnn(ocl): fix conv BASIC workgroup

modules/dnn/src/ocl4dnn/src/ocl4dnn_conv_spatial.cpp

@@ -1081,9 +1081,16 @@ bool OCL4DNNConvSpatial<float>::convolve(const UMat &bottom, UMat &top,
                 kernel.set(argIdx++, (uint16_t)output_h_);
                 kernel.set(argIdx++, (uint16_t)pad_w_);
                 kernel.set(argIdx++, (uint16_t)pad_h_);
-                if (!kernel.run_(3, config->global_work_size,
-                                (config->use_null_local) ? NULL : config->local_work_size,
-                                false))
+
+                size_t wgs = kernel.workGroupSize();
+                if (!wgs)
+                {
+                    CV_LOG_ERROR(NULL, "DNN/OpenCL: Can't query workGroupSize of Basic kernel");
+                    return false;
+                }
+                size_t lws[1] = { wgs };
+                size_t gws[1] = { roundUp((size_t)output_w_ * output_h_ * M_, (unsigned)lws[0]) };
+                if (!kernel.run_(1, gws, lws, false))
                 {
                     CV_LOG_ERROR(NULL, "DNN/OpenCL: Basic kernel run failed");
                     return false;

modules/dnn/src/opencl/conv_layer_spatial.cl

@@ -158,10 +158,14 @@ __kernel void ConvolveBasic(
 )
 {
     __global Dtype* convolved_image = convolved_image_base + convolved_image_base_offset;
-    const int outputX = get_global_id(0);
-    const int outputY = get_global_id(1);
-    const int kernelNum = get_global_id(2) * ZPAR;
-    if (outputX < output_width && outputY < output_height)
+    const int out_idx = get_global_id(0);  // 1D task layout: [output_width * output_height * OUTPUT_Z]
+    const int plane_size = output_width * output_height;
+    const int out_plane_idx = out_idx % plane_size;
+    const int outputZ = out_idx / plane_size;
+    const int outputY = out_plane_idx / output_width;
+    const int outputX = out_plane_idx % output_width;
+    const int kernelNum = outputZ * ZPAR;
+    if (kernelNum < OUTPUT_Z)
     {
         Dtype sum[ZPAR];
         for (int kern = 0; kern < ZPAR; kern++)