HelenOS sources

CTRL_FRCSPD       411 uspace/drv/nic/e1k/e1k.c 	ctrl |= CTRL_FRCSPD;
CTRL_FRCSPD       453 uspace/drv/nic/e1k/e1k.c 	ctrl &= ~(CTRL_FRCSPD);
CTRL_FRCSPD       481 uspace/drv/nic/e1k/e1k.c 	ctrl |= CTRL_FRCSPD;
HelenOS homepage, sources at GitHub