AMDMSR(4) - Device Drivers Manual (i386) #

AMDMSR(4) - Device Drivers Manual (i386)

NAME #

amdmsr - access MSRs on certain AMD Geode LX systems

SYNOPSIS #

amdmsr0 at mainbus?

DESCRIPTION #

The amdmsr device provides access to the Model Specific Registers (MSRs) on systems with an AMD Geode LX CPU and graphics processor.

IOCTL INTERFACE #

MSRs can be read or written via ioctl() calls performed on /dev/amdmsr. Declarations and data types are to be found in <machine/amdmsr.h>.

Read or write requests are performed using:

struct amdmsr_req {
	u_int32_t addr;	/* 32-bit MSR address */
	u_int64_t val;	/* 64-bit MSR value */
};

The RDMSR ioctl is used to read an MSR register.

The WRMSR ioctl is used to write an MSR register.

SEE ALSO #

ioctl(2)

HISTORY #

amdmsr support was added in OpenBSD 4.4.

OpenBSD 7.5 - January 21, 2014