diff --git a/src/intel/compiler/brw_lower_logical_sends.cpp b/src/intel/compiler/brw_lower_logical_sends.cpp
index 2405fb4f6f4..b7610a1347a 100644
--- a/src/intel/compiler/brw_lower_logical_sends.cpp
+++ b/src/intel/compiler/brw_lower_logical_sends.cpp
@@ -2597,9 +2597,18 @@ lower_interpolator_logical_send(const fs_builder &bld, fs_inst *inst,
       unreachable("Invalid interpolator instruction");
    }
 
+   const bool dynamic_mode =
+      inst->opcode == FS_OPCODE_INTERPOLATE_AT_SAMPLE &&
+      wm_prog_data->persample_dispatch == BRW_SOMETIMES;
+
    fs_reg desc = inst->src[1];
    uint32_t desc_imm =
-      brw_pixel_interp_desc(devinfo, mode, inst->pi_noperspective,
+      brw_pixel_interp_desc(devinfo,
+                            /* Leave the mode at 0 if persample_dispatch is
+                             * dynamic, it will be ORed in below.
+                             */
+                            dynamic_mode ? 0 : mode,
+                            inst->pi_noperspective,
                             false /* coarse_pixel_rate */,
                             inst->exec_size, inst->group);
 
@@ -2613,7 +2622,7 @@ lower_interpolator_logical_send(const fs_builder &bld, fs_inst *inst,
       ubld.AND(desc, dynamic_msaa_flags(wm_prog_data),
                brw_imm_ud(BRW_WM_MSAA_FLAG_COARSE_PI_MSG));
 
-   /* And, if it's AT_OFFSET, we might have a non-trivial descriptor */
+      /* And, if it's AT_OFFSET, we might have a non-trivial descriptor */
       if (orig_desc.file == IMM) {
          desc_imm |= orig_desc.ud;
       } else {
@@ -2621,6 +2630,48 @@ lower_interpolator_logical_send(const fs_builder &bld, fs_inst *inst,
       }
    }
 
+   /* If persample_dispatch is dynamic, select the interpolation mode
+    * dynamically and OR into the descriptor to complete the static part
+    * generated by brw_pixel_interp_desc().
+    *
+    * Why does this work? If you look at the SKL PRMs, Volume 7:
+    * 3D-Media-GPGPU, Shared Functions Pixel Interpolater, you'll see that
+    *
+    *   - "Per Message Offset” Message Descriptor
+    *   - “Sample Position Offset” Message Descriptor
+    *
+    * have different formats. Fortunately, a fragment shader dispatched at
+    * pixel rate, will have gl_SampleID = 0 & gl_NumSamples = 1. So the value
+    * we pack in “Sample Position Offset” will be a 0 and will cover the X/Y
+    * components of "Per Message Offset”, which will give us the pixel offset 0x0.
+    */
+   if (dynamic_mode) {
+      fs_reg orig_desc = desc;
+      const fs_builder &ubld = bld.exec_all().group(8, 0);
+      desc = ubld.vgrf(BRW_REGISTER_TYPE_UD);
+
+      check_dynamic_msaa_flag(ubld, wm_prog_data,
+                              BRW_WM_MSAA_FLAG_PERSAMPLE_DISPATCH);
+      if (orig_desc.file == IMM) {
+         /* Not using SEL here because we would generate an instruction with 2
+          * immediate sources which is not supported by HW.
+          */
+         set_predicate_inv(BRW_PREDICATE_NORMAL, false,
+                           ubld.MOV(desc, brw_imm_ud(orig_desc.ud |
+                                                     GFX7_PIXEL_INTERPOLATOR_LOC_SAMPLE << 12)));
+         set_predicate_inv(BRW_PREDICATE_NORMAL, true,
+                           ubld.MOV(desc, brw_imm_ud(orig_desc.ud |
+                                                     GFX7_PIXEL_INTERPOLATOR_LOC_SHARED_OFFSET << 12)));
+      } else {
+         set_predicate_inv(BRW_PREDICATE_NORMAL, false,
+                           ubld.OR(desc, orig_desc,
+                                   brw_imm_ud(GFX7_PIXEL_INTERPOLATOR_LOC_SAMPLE << 12)));
+         set_predicate_inv(BRW_PREDICATE_NORMAL, true,
+                           ubld.OR(desc, orig_desc,
+                                   brw_imm_ud(GFX7_PIXEL_INTERPOLATOR_LOC_SHARED_OFFSET << 12)));
+      }
+   }
+
    assert(bld.shader->devinfo->ver >= 7);
    inst->opcode = SHADER_OPCODE_SEND;
    inst->sfid = GFX7_SFID_PIXEL_INTERPOLATOR;