INTEL_REG(1) General Commands Manual INTEL_REG(1)
intel_reg – Intel graphics register multitool
intel_reg [option …] command
Intel graphics register multitool. Read, write, dump, and decode Intel
graphics MMIO and sideband registers, and more.
Some options are global, and some specific to commands.
Read N registers.
Output binary values.
Decode registers for all known platforms.
Use MMIO bar from FILE.
Pretend to be PCI ID DEVID. Useful with MMIO bar snapshots from other
Read register spec from directory or file specified by PATH; see REGIS‐
TER SPEC DEFINITIONS below for details.
Show brief help.
See REGISTER REFERENCES below on how to describe registers for the com‐
read [–count=N] REGISTER […]
Dump each specified REGISTER, or N registers starting from each REGIS‐
write REGISTER VALUE [REGISTER VALUE …] Write each VALUE to corresponding REGISTER.
dump [–mmio=FILE –devid=DEVID] Dump all registers specified in the register spec.
decode REGISTER VALUE
Decode REGISTER VALUE.
Output the MMIO bar to stdout. The output can be used for a later invo‐
cation of dump or read with the –mmio=FILE and –devid=DEVID parame‐
List the known registers.
Display brief help.
Registers are defined as [(PORTNAME|PORTNUM|MMIO-OFFSET):](REG‐
The register access method, most often MMIO, which is the default. The
methods supported on all platforms are “mmio”, “portio-vga”, and
On BYT and CHV, the sideband ports “bunit”, “punit”, “nc”, “dpio”,
“gpio-nc”, “cck”, “ccu”, “dpio2”, and “flisdsi” are also supported.
Port number for the sideband ports supported on BYT and CHV. Only num‐
bers mapped to the supported ports are allowed, arbitrary numbers are
Numbers above 0xff are automatically interpreted as MMIO offsets, not
Use MMIO, and add this offset to the register address.
Numbers equal to or below 0xff are automatically interpreted as port
numbers, not MMIO offsets.
Name of the register as defined in the register spec.
If MMIO offset is not specified, it is picked up from the register
spec. However, ports are not; the port is a namespace for the register
Register address. The corresponding register name need not be specified
in the register spec.
Path to a directory or a file containing register spec definitions.
A register spec associates register names with addresses. The spec is
searched for in this order:
1. Directory or file specified by the –spec option.
2. Directory or file specified by the INTEL_REG_SPEC environment vari‐
3. Builtin register spec. Also used as fallback with a warning if the
above are used but fail.
If a directory is specified using –spec option or INTEL_REG_SPEC envi‐
ronment variable, the directory is scanned for a spec file in this
1. File named after the PCI device id. For example, “0412”.
2. File named after the code name in lowercase, without punctuation.
For example, “valleyview”.
3. File named after generation. For example, “gen7” (note that this
matches valleyview, ivybridge and haswell!).
Register Spec File Format
The register spec format is briefly described below:
· Empty lines and lines beginning with “#”, “;”, or “//” are ignored.
· Lines not beginning with “(” are interpreted as file names, absolute
or relative, to be included.
· Lines beginning with “(” are interpreted as register definitions.
Registers are defined as tuples (‘REGNAME’, ‘REGADDR’, ‘PORTNAME|PORT‐
NUM|MMIO-OFFSET’), as in REGISTER REFERENCES above. The port descrip‐
tion may also be an empty string to denote MMIO.
· # this is a comment, below is an include
· (‘GEN6_PMINTRMSK’, ‘0x0000a168’, ”)
· (‘MIPIA_PORT_CTRL’, ‘0x61190’, ‘0x180000’)
· (‘PLL1_DW0’, ‘0x8000’, ‘DPIO’)
Reading some registers may hang the GPU or the machine.
2015 Intel Corporation
intel-gpu-tools 2015-04-14 INTEL_REG(1)