Index: uspace/drv/nic/rtl8139/driver.c
===================================================================
--- uspace/drv/nic/rtl8139/driver.c	(revision 36470ce8f1d0f0e1ac58746fc8bd8bf3bed80974)
+++ uspace/drv/nic/rtl8139/driver.c	(revision f712a858b9463dae30e9eee5ef1ccc54ae618f02)
@@ -201,4 +201,9 @@
 	    ddf_dev_parent_sess_get(nic_get_ddf_dev(rtl8139->nic_data));
 
+	// XXX: According to the RTL8139C(L) Rev.1.4 datasheet, the entire PCI
+	// Power Management data structure is located at a fixed address 0x50 so
+	// that PME_Status and PME_En find themselves at address 0x55. It would
+	// be more flexible though to locate the data structure by searching
+	// the PCI function's capability list.
 	if (bit_val) {
 		uint8_t pmen;