Must Be One [LWN.net]

Must Be One

Posted Nov 24, 2011 17:36 UTC (Thu) by wildea01 (subscriber, #71011)
Parent article: Drivers as documentation

There's a lovely bit in the hardware configuration register for the SMSC9118 ethernet controller:

BIT: 20
DESCRIPTION: Must Be One (MBO). This bit must be set to 1 for normal device operation
TYPE: R/W
DEFAULT (reset value): 0

We do at least set it in Linux, but it's a bit cryptic:

#define HW_CFG_SF_ (0x00100000) /* R/W */

God knows what it's really doing.

(Log in to post comments)