dmesg
Linux Commands - Administrative Commands

dmesg

 

This command provides the information that flashed across the screen during

startup.

 

Example:

 

dmesg | less

 

This command will help you go through one page at a time so you can read it.

 

Here is an example;

 

Linux version 2.6.10-5-386 (buildd@vernadsky) (gcc version 3.3.5 (Debian 1:3.3.5-8ubuntu2)) #1 Fri Jun 24 16:53:01 UTC 2005

BIOS-provided physical RAM map:

BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)

BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)

BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)

BIOS-e820: 0000000000100000 - 000000000fff0000 (usable)

BIOS-e820: 000000000fff0000 - 000000000fff3800 (reserved)

BIOS-e820: 000000000fff3800 - 0000000010000000 (ACPI NVS)

255MB LOWMEM available.

On node 0 totalpages: 65520

DMA zone: 4096 pages, LIFO batch:1

Normal zone: 61424 pages, LIFO batch:14

HighMem zone: 0 pages, LIFO batch:1

DMI 2.3 present.

ACPI: RSDP (v000 COMPAQ ) @ 0x000f9970

ACPI: RSDT (v001 COMPAQ RSDTBL 0x00000001 CPQ 0x00000001) @ 0x0fff476d

ACPI: FADT (v001 COMPAQ CPQB151 0x20020315 CPQ 0x00000001) @ 0x0fff4828

ACPI: SSDT (v001 COMPAQ CPQGysr 0x00001001 MSFT 0x0100000c) @ 0x0fff4799

ACPI: DSDT (v001 COMPAQ ARMADAE7 0x00010000 MSFT 0x0100000c) @ 0x00000000

ACPI: PM-Timer IO Port: 0x5008

Built 1 zonelists

Kernel command line: root=/dev/hda1 ro quiet splash

Local APIC disabled by BIOS -- you can enable it with "lapic"

mapped APIC to ffffd000 (01203000)

Initializing CPU#0

PID hash table entries: 1024 (order: 10, 16384 bytes)

Detected 995.720 MHz processor.

Using pmtmr for high-res timesource

Console: colour VGA+ 80x25

Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)

Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)

Memory: 252060k/262080k available (1436k kernel code, 9404k reserved, 754k data, 224k init, 0k highmem)

Checking if this processor honours the WP bit even in supervisor mode... Ok.

Calibrating delay loop... 1974.27 BogoMIPS (lpj=987136)

Security Framework v1.0.0 initialized

SELinux: Disabled at boot.

Mount-cache hash table entries: 512 (order: 0, 4096 bytes)

CPU: After generic identify, caps: 0383f9ff 00000000 00000000 00000000 00000000 00000000

CPU: After vendor identify, caps: 0383f9ff 00000000 00000000 00000000 00000000 00000000

CPU: L1 I cache: 16K, L1 D cache: 16K

CPU: L2 cache: 256K

CPU: After all inits, caps: 0383f9ff 00000000 00000000 00000040 00000000 00000000

CPU: Intel Pentium III (Coppermine) stepping 0a

Enabling fast FPU save and restore... done.

Enabling unmasked SIMD FPU exception support... done.

Checking 'hlt' instruction... OK.

Checking for popad bug... OK.

ACPI: Looking for DSDT in initrd... not found!

ACPI: setting ELCR to 0200 (from 0800)

checking if image is initramfs...it isn't (bad gzip magic numbers); looks like an initrd

Freeing initrd memory: 4300k freed

NET: Registered protocol family 16

EISA bus registered

PCI: PCI BIOS revision 2.10 entry at 0xf0478, last bus=1

PCI: Using configuration type 1

mtrr: v2.0 (20020519)

ACPI: Subsystem revision 20050211

ACPI: Interpreter enabled

ACPI: Using PIC for interrupt routing

ACPI: PCI Root Bridge [C005] (00:00)

PCI: Probing PCI hardware (bus 00)

ACPI: PCI Interrupt Routing Table [\_SB_.C005._PRT]

ACPI: Power Resource [C129] (on)

ACPI: Power Resource [C0DB] (on)

ACPI: PCI Interrupt Link [C142] (IRQs *11)

ACPI: PCI Interrupt Link [C148] (IRQs 11) *0, disabled.

ACPI: PCI Interrupt Link [C149] (IRQs *11)

ACPI: PCI Interrupt Link [C14A] (IRQs *11)

ACPI: Power Resource [C15F] (off)

ACPI: Power Resource [C161] (off)

ACPI: Power Resource [C163] (off)

Linux Plug and Play Support v0.97 (c) Adam Belay

pnp: PnP ACPI init

pnp: PnP ACPI: found 15 devices

PnPBIOS: Disabled by ACPI PNP

PCI: Using ACPI for IRQ routing

** PCI interrupts are no longer routed automatically. If this

** causes a device to stop working, it is probably because the

** driver failed to call pci_enable_device(). As a temporary

** workaround, the "pci=routeirq" argument restores the old

** behavior. If this argument makes the device work again,

** please email the output of "lspci" to This e-mail address is being protected from spambots. You need JavaScript enabled to view it

** so I can fix the driver.

PCI: Cannot allocate resource region 4 of device 0000:00:07.1

pnp: 00:0c: ioport range 0x4d0-0x4d1 has been reserved

pnp: 00:0c: ioport range 0x800-0x87f has been reserved

pnp: 00:0c: ioport range 0x4000-0x400f has been reserved

pnp: 00:0c: ioport range 0x5000-0x5063 could not be reserved

pnp: 00:0c: ioport range 0x6004-0x6005 could not be reserved

pnp: 00:0c: ioport range 0xf000-0xf0cf has been reserved

audit: initializing netlink socket (disabled)

audit(1124158427.917:0): initialized

VFS: Disk quotas dquot_6.5.1

Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)

devfs: 2004-01-31 Richard Gooch ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it )

devfs: boot_options: 0x0

Initializing Cryptographic API

Limiting direct PCI/PCI transfers.

isapnp: Scanning for PnP cards...

isapnp: No Plug & Play device found

i8042.c: Detected active multiplexing controller, rev 1.0.

serio: i8042 AUX0 port at 0x60,0x64 irq 12

serio: i8042 AUX1 port at 0x60,0x64 irq 12

serio: i8042 AUX2 port at 0x60,0x64 irq 12

serio: i8042 AUX3 port at 0x60,0x64 irq 12

serio: i8042 KBD port at 0x60,0x64 irq 1

Serial: 8250/16550 driver $Revision: 1.90 $ 54 ports, IRQ sharing enabled

ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

ttyS2 at I/O 0x3e8 (irq = 4) is a 16550A

ACPI: PCI Interrupt Link [C149] enabled at IRQ 11

PCI: setting IRQ 11 as level-triggered

ACPI: PCI interrupt 0000:00:09.1[A] -> GSI 11 (level, low) -> IRQ 11

ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

io scheduler noop registered

io scheduler anticipatory registered

io scheduler deadline registered

io scheduler cfq registered

RAMDISK driver initialized: 16 RAM disks of 8192K size 1024 blocksize

input: AT Translated Set 2 keyboard on isa0060/serio0

EISA: Probing bus 0 at eisa0

Cannot allocate resource for EISA slot 1

Cannot allocate resource for EISA slot 3

Cannot allocate resource for EISA slot 4

Cannot allocate resource for EISA slot 5

Cannot allocate resource for EISA slot 6

EISA: Detected 0 cards.

NET: Registered protocol family 2

IP: routing cache hash table of 2048 buckets, 16Kbytes

TCP: Hash tables configured (established 16384 bind 32768)

NET: Registered protocol family 8

NET: Registered protocol family 20

Restarting tasks...<6> Strange, kswapd0 not stopped

Strange, kseriod not stopped

done

ACPI wakeup devices:

C005 C0AE C14B C057 C16B

ACPI: (supports S0 S1 S3 S4 S4bios S5)

RAMDISK: cramfs filesystem found at block 0

RAMDISK: Loading 4300KiB [1 disk] into ram disk... done.

VFS: Mounted root (cramfs filesystem) readonly.

Freeing unused kernel memory: 224k freed

ACPI: Fan [C15D] (off)

ACPI: Fan [C160] (off)

ACPI: Fan [C162] (off)

ACPI: CPU0 (power states: C1[C1] C2[C2])

ACPI: Processor [C0B4] (supports 8 throttling states)

ACPI: Thermal Zone [C15E] (42 C)

NET: Registered protocol family 1

Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2

ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx

PIIX4: IDE controller at PCI slot 0000:00:07.1

PIIX4: chipset revision 1

PIIX4: not 100% native mode: will probe irqs later

ide0: BM-DMA at 0x1000-0x1007, BIOS settings: hda:DMA, hdb:DMA

Probing IDE interface ide0...

hda: TOSHIBA MK1516GAP, ATA DISK drive

hdb: Compaq CRN-8241B, ATAPI CD/DVD-ROM drive

elevator: using anticipatory as default io scheduleride0 at 0x1f0-0x1f7,0x3f6 on irq 14

hda: max request size: 128KiB

hda: 23579136 sectors (12072 MB), CHS=23392/16/63, UDMA(33)

hda: cache flushes not supported

/dev/ide/host0/bus0/target0/lun0: p1 p2 < p5 >

Probing IDE interface ide1...

ide2: I/O resource 0x3EE-0x3EE not free.

ide2: ports already in use, skipping probe

Probing IDE interface ide3...

Probing IDE interface ide4...

Probing IDE interface ide5...

Stopping tasks: ==|

Freeing memory... done (458 pages freed)

Restarting tasks... done

EXT3-fs: mounted filesystem with ordered data mode.

kjournald starting. Commit interval 5 seconds

Adding 514040k swap on /dev/hda5. Priority:-1 extents:1

EXT3 FS on hda1, internal journal

hdb: ATAPI 24X CD-ROM drive, 128kB Cache

Uniform CD-ROM driver Revision: 3.20

parport: PnPBIOS parport detected.

parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE,EPP]

lp0: using parport0 (interrupt-driven).

mice: PS/2 mouse device common for all mice

Synaptics Touchpad, model: 1

Firmware: 5.6

Sensor: 22

new absolute packet format

Touchpad has extended capability bits

-> multifinger detection

-> palm detection

input: SynPS/2 Synaptics TouchPad on isa0060/serio4

ts: Compaq touchscreen protocol output

Capability LSM initialized

device-mapper: 4.3.0-ioctl (2004-09-30) initialised: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

md: md driver 0.90.1 MAX_MD_DEVS=256, MD_SB_DISKS=27hdb: packet command error: status=0x51 { DriveReady SeekComplete Error }

hdb: packet command error: error=0x54

ide: failed opcode was 100

cdrom: open failed.

inserting floppy driver for 2.6.10-5-386

Floppy drive(s): fd0 is 1.44M

FDC 0 is a post-1991 82077

irda_init()

NET: Registered protocol family 23

input: PC Speaker

Real Time Clock Driver v1.12

Linux agpgart interface v0.100 (c) Dave Jones

agpgart: Detected an Intel 440BX Chipset.

agpgart: Maximum main memory to use for agp memory: 203M

agpgart: AGP aperture is 64M @ 0x50000000

cpci_hotplug: CompactPCI Hot Plug Core version: 0.2

pci_hotplug: PCI Hot Plug PCI Core version: 0.5

shpchp: acpi_shpchprm:\_SB_.C005 evaluate _BBN fail=0x5

shpchp: acpi_shpchprm:get_device PCI ROOT HID fail=0x5

pciehp: acpi_pciehprm:\_SB_.C005 evaluate _BBN fail=0x5

pciehp: acpi_pciehprm:get_device PCI ROOT HID fail=0x5

Linux Kernel Card Services

options: [pci] [cardbus] [pm]

ACPI: PCI Interrupt Link [C142] enabled at IRQ 11

ACPI: PCI interrupt 0000:00:04.0[A] -> GSI 11 (level, low) -> IRQ 11

Yenta: CardBus bridge found at 0000:00:04.0 [0e11:b121]

Yenta: Enabling burst memory read transactions

Yenta: Using CSCINT to route CSC interrupts to PCI

Yenta: Routing CardBus interrupts to PCI

Yenta TI: socket 0000:00:04.0, mfunc 0x01001c72, devctl 0x64

Yenta: ISA IRQ mask 0x0438, PCI irq 11

Socket status: 30000006

ACPI: PCI interrupt 0000:00:04.1[A] -> GSI 11 (level, low) -> IRQ 11

Yenta: CardBus bridge found at 0000:00:04.1 [0e11:b121]

Yenta: Using CSCINT to route CSC interrupts to PCI

Yenta: Routing CardBus interrupts to PCI

Yenta TI: socket 0000:00:04.1, mfunc 0x01001c72, devctl 0x64

Yenta: ISA IRQ mask 0x0438, PCI irq 11

Socket status: 30000006

usbcore: registered new driver usbfs

usbcore: registered new driver hub

USB Universal Host Controller Interface driver v2.2

ACPI: PCI Interrupt Link [C14A] enabled at IRQ 11

ACPI: PCI interrupt 0000:00:07.2[D] -> GSI 11 (level, low) -> IRQ 11

uhci_hcd 0000:00:07.2: Intel Corp. 82371AB/EB/MB PIIX4 USB

uhci_hcd 0000:00:07.2: irq 11, io base 0x4020

uhci_hcd 0000:00:07.2: new USB bus registered, assigned bus number 1

hub 1-0:1.0: USB hub found

hub 1-0:1.0: 2 ports detected

usb 1-1: new low speed USB device using uhci_hcd and address 2

piix4_smbus 0000:00:07.3: Found 0000:00:07.3 device

usbcore: registered new driver hiddev

input: USB HID v1.10 Mouse [Logitech USB Receiver] on usb-0000:00:07.2-1

usbcore: registered new driver usbhid

drivers/usb/input/hid-core.c: v2.0:USB HID core driver

ACPI: PCI interrupt 0000:00:08.0[A] -> GSI 11 (level, low) -> IRQ 11

es1968: clocking to 48000

e100: Intel(R) PRO/100 Network Driver, 3.2.3-k2-NAPIe100: Copyright(c) 1999-2004 Intel Corporation

ACPI: PCI interrupt 0000:00:09.0[A] -> GSI 11 (level, low) -> IRQ 11

e100: eth0: e100_probe: addr 0x41280000, irq 11, MAC addr 00:D0:59:9C:3D:FC

e100: eth0: e100_watchdog: link up, 10Mbps, half-duplex

NET: Registered protocol family 17

NET: Registered protocol family 10

Disabled Privacy Extensions on device c02f0500(lo)

IPv6 over IPv4 tunneling driver

ACPI: AC Adapter [C0F6] (on-line)

ACPI: Battery Slot [C0FE] (battery present)

ACPI: Battery Slot [C0FF] (battery absent)

ACPI: Battery Slot [C100] (battery absent)

ACPI: Power Button (FF) [PWRF]

ACPI: Sleep Button (CM) [C057]

ACPI: Lid Switch [C16B]

ibm_acpi: ec object not found

apm: BIOS version 1.2 Flags 0x03 (Driver version 1.16ac)

apm: overridden by ACPI.

mtrr: 0x40000000,0x800000 overlaps existing 0x40000000,0x400000

mtrr: 0x40000000,0x800000 overlaps existing 0x40000000,0x400000

ip_tables: (C) 2000-2002 Netfilter core team

ip_conntrack version 2.1 (2047 buckets, 16376 max) - 336 bytes per conntrack

eth0: no IPv6 routers present

cs: IO port probe 0x0100-0x04ff: excluding 0x100-0x107

cs: IO port probe 0x0800-0x08ff: clean.

cs: IO port probe 0x0c00-0x0cff: clean.

cs: IO port probe 0x0a00-0x0aff: clean.

e100: eth0: e100_watchdog: link down

e100: eth0: e100_watchdog: link up, 10Mbps, half-duplex

 

 

As you review the example you can see it would be a great aid in troubleshooting problems because it shows the hardware status of the machine and how it is interacting with the software and kernel. Notice the important role that ACPI plays in managing both power and hardware.