diff --git a/src/common.h b/src/common.h
index 2a9a8fc..547f445 100644
--- a/src/common.h
+++ b/src/common.h
@@ -1095,7 +1095,7 @@ parse_vsync(session_t *ps, const char *str) {
       return true;
     }
 
-  printf_errf("(\"%s\"): Invalid vsync argument.", str);
+  log_error("Invalid vsync argument: %s", str);
   return false;
 }
 
@@ -1119,7 +1119,7 @@ parse_backend(session_t *ps, const char *str) {
     ps->o.backend = BKEND_XR_GLX_HYBRID;
     return true;
   }
-  printf_errf("(\"%s\"): Invalid backend argument.", str);
+  log_error("Invalid backend argument: %s", str);
   return false;
 }
 
@@ -1154,18 +1154,18 @@ parse_glx_swap_method(session_t *ps, const char *str) {
     char *pc = NULL;
     int age = strtol(str, &pc, 0);
     if (!pc || str == pc) {
-      printf_errf("(\"%s\"): Invalid number.", str);
+      log_error("glx-swap-method is an invalid number: %s", str);
       return false;
     }
 
     for (; *pc; ++pc)
       if (!isspace(*pc)) {
-        printf_errf("(\"%s\"): Trailing characters.", str);
+        log_error("Trailing characters in glx-swap-method option: %s", str);
         return false;
       }
 
     if (age > CGLX_MAX_BUFFER_AGE + 1 || age < -1) {
-      printf_errf("(\"%s\"): Number too large / too small.", str);
+      log_error("Number for glx-swap-method is too large / too small: %s", str);
       return false;
     }
 
@@ -1495,7 +1495,7 @@ xr_sync(session_t *ps, Drawable d, XSyncFence *pfence) {
       assert(!XSyncQueryFence(ps->dpy, *pfence, &triggered) || triggered);
     }
     else {
-      printf_errf("(%#010lx): Failed to create X Sync fence.", d);
+      log_error("Failed to create X Sync fence for %#010lx", d);
     }
     free_fence(ps, &tmp_fence);
     if (*pfence)
@@ -1561,63 +1561,6 @@ opts_set_no_fading_openclose(session_t *ps, bool newval);
 //!@}
 #endif
 
-/**
- * @brief Dump the given data to a file.
- */
-static inline bool
-write_binary_data(const char *path, const unsigned char *data, int length) {
-  if (!data)
-    return false;
-  FILE *f = fopen(path, "wb");
-  if (!f) {
-    printf_errf("(\"%s\"): Failed to open file for writing.", path);
-    return false;
-  }
-  int wrote_len = fwrite(data, sizeof(unsigned char), length, f);
-  fclose(f);
-  if (wrote_len != length) {
-    printf_errf("(\"%s\"): Failed to write all blocks: %d / %d", path,
-        wrote_len, length);
-    return false;
-  }
-  return true;
-}
-
-/**
- * @brief Dump raw bytes in HEX format.
- *
- * @param data pointer to raw data
- * @param len length of data
- */
-static inline void
-hexdump(const char *data, int len) {
-  static const int BYTE_PER_LN = 16;
-
-  if (len <= 0)
-    return;
-
-  // Print header
-  printf("%10s:", "Offset");
-  for (int i = 0; i < BYTE_PER_LN; ++i)
-    printf(" %2d", i);
-  putchar('\n');
-
-  // Dump content
-  for (int offset = 0; offset < len; ++offset) {
-    if (!(offset % BYTE_PER_LN))
-      printf("0x%08x:", offset);
-
-    printf(" %02hhx", data[offset]);
-
-    if ((BYTE_PER_LN - 1) == offset % BYTE_PER_LN)
-      putchar('\n');
-  }
-  if (len % BYTE_PER_LN)
-    putchar('\n');
-
-  fflush(stdout);
-}
-
 /**
  * Set a <code>bool</code> array of all wintypes to true.
  */
diff --git a/src/compton.c b/src/compton.c
index 2abafd4..fda509c 100644
--- a/src/compton.c
+++ b/src/compton.c
@@ -4046,7 +4046,28 @@ session_destroy(session_t *ps) {
   log_deinit_tls();
 }
 
-/*
+#if 0
+/**
+ * @brief Dump the given data to a file.
+ */
+static inline bool
+write_binary_data(const char *path, const unsigned char *data, int length) {
+  if (!data)
+    return false;
+  FILE *f = fopen(path, "wb");
+  if (!f) {
+    log_error("Failed to open \"%s\" for writing.", path);
+    return false;
+  }
+  int wrote_len = fwrite(data, sizeof(unsigned char), length, f);
+  fclose(f);
+  if (wrote_len != length) {
+    printf_errf("(\"%s\"): Failed to write all blocks: %d / %d", path,
+        wrote_len, length);
+    return false;
+  }
+  return true;
+}
 static inline void
 dump_img(session_t *ps) {
   int len = 0;
@@ -4054,7 +4075,7 @@ dump_img(session_t *ps) {
   write_binary_data("/tmp/dump.raw", d, len);
   free(d);
 }
-*/
+#endif
 
 /**
  * Do the actual work.