Hack 93 Display Hardware Information

If you're new to FreeBSD, you may be wondering where to find information about your system's hardware and the resources it uses.

You've probably noticed that your FreeBSD system didn't ship with a Microsoft-style Device Manager. However, it does have plenty of useful utilities for gathering hardware information.

9.6.1 Viewing Boot Messages

When you boot your system, the kernel probes your hardware devices and displays the results to your screen. You can view these messages, even before you log in, by pressing the scroll lock key and using your up arrow to scroll back through the message buffer. When you're finished, press scroll lock again to return to the login or command prompt.

You can type dmesg any time you need to read the system message buffer. However, if it's been a while since bootup, it's quite possible that system messages have overwritten the boot messages. If so, look in the file /var/run/dmesg.boot, which contains the messages from the latest boot. This is an ASCII text file, so you can send it to a pager such as more or less.

You may find it more convenient to search for something particular. For example, suppose you've added sound support to your kernel by adding device pcm to your kernel configuration file. This command will show if the PCM device was successfully loaded by the new kernel:

% grep pcm /var/run/dmesg.boot

pcm0: <Creative CT5880-C> port 0xa800-0xa83f irq 10 at device 7.0 on pci0

pcm0: <SigmaTel STAC9708/11 AC97 Codec>

In this example, the kernel did indeed probe my Creative sound card at bootup.

9.6.2 Viewing Resource Information

Sometimes you just want to know which devices are using which system resources. This command will display the IRQs, DMAs, I/O ports, and I/O memory addresses in use:

% devinfo -u

Interrupt request lines:

    0 (root0)

    1 (atkbd0)

    2 (root0)

    3 (sio1)

    4 (sio0)

    5 (rl0)

    6 (fdc0)

    7 (ppc0)

    8 (root0)

    9 (acpi0)

    10 (pcm0)

    11 (rl1)

    12 (psm0)

    13 (root0)

    14 (ata0)

    15 (ata1)

DMA request lines:

    0-1 (root0)

    2 (fdc0)

    3 (ppc0)

    4-7 (root0)

I/O ports:

    0x0-0xf (root0)

    0x10-0x1f (acpi_sysresource0)

    0x20-0x21 (root0)

<snip>

I/O memory addresses:

    0x0-0x9ffff (root0)

    0xa0000-0xbffff (vga0)

    0xc0000-0xcbfff (orm0)

    0xcc000-0xfbffffff (root0)

    0xfc000000-0xfdffffff (agp0)

    0xfe000000-0xffffffff (root0)

Alternately, use devinfo -r if you prefer to see your listing by device.

If you're unsure what a device is, use the whatis command. For example, in my listing, ppc0 uses IRQ 7 and DMA 3. To find out what ppc0 is:

% whatis ppc

ppc(4)         Parallel Port Chipset driver

Don't include the trailing number when using the whatis command.

9.6.3 Gathering Interface Statistics

There are several ways to gather network interface information. One of the handiest is the -i switch to netstat:

% netstat -i

Name    Mtu Network       Address            Ipkts Ierrs  Opkts Oerrs  Coll

rl0*   1500 <Link#1>      00:05:5d:d2:19:b7    0     0        0     0     0

rl1*   1500 <Link#2>      00:05:5d:d1:ff:9d    0     0        0     0     0

ed0    1500 <Link#3>      00:50:ba:de:36:33  15247   0     11301    0    78

ed0    1500 192.168.2     genisis.           15091   -     11222    -     -

lp0*   1500 <Link#4>                           0     0        0     0     0

lo0   16384 <Link#5>                         179     0      179     0     0

lo0   16384 your-net      localhost          179     -      179     -     -

This command shows all interfaces, both physical and virtual. This particular system has three network interface cards: rl0, rl1, and ed0. The first two interfaces are shut down, as indicated by the * after the device name. These three are Ethernet cards, as indicated by their MAC addresses. (This is also an excellent way to find all of the MAC addresses on your system).

The ed0 interface and loopback interface (lo0) have each been configured with a hostname and an IP address, as indicated by the Network column. If you're only interested in seeing interfaces configured with an IPv4 address, add the -f (family) switch:

% netstat -i -f inet

ed0    1500 192.168.2     genisis.           15091   -     11222    -     -

lo0   16384 your-net      localhost          179     -      179     -     -

9.6.4 Viewing Kernel Environment

You can also find hardware information by using kenv to view your kernel environment. kenv will dump several screens worth of information, so use grep when possible to zero in on the information you want. For example, to view IRQ information:

% kenv | grep irq

hint.ata.0.irq="14"

hint.ata.1.irq="15"

hint.atkbd.0.irq="1"

hint.ed.0.irq="10"

hint.fdc.0.irq="6"

hint.ie.0.irq="10"

hint.le.0.irq="5"

hint.lnc.0.irq="10"

hint.pcic.1.irq="11"

hint.ppc.0.irq="7"

hint.psm.0.irq="12"

hint.sio.0.irq="4"

hint.sio.1.irq="3"

hint.sio.2.irq="5"

hint.sio.3.irq="9"

hint.sn.0.irq="10"

If you're unsure what is using a listed IRQ, use whatis to look up the second word (the one after hint). For example, this will show what is using my IRQ 12:

% whatis psm

psm(4)      - PS/2 mouse style pointing device driver

I actually prefer the output of kenv to that of devinfo. Here, I'll search for the I/O addresses used by my COM ports:

% kenv | grep port | grep sio

hint.sio.0.port="0x3F8"

hint.sio.1.port="0x2F8"

hint.sio.2.port="0x3E8"

hint.sio.3.port="0x2E8"

To see which devices are disabled:

% kenv | grep disabled

hint.sio.2.disabled="1"

hint.sio.3.disabled="1"

BSD gives the first com port the number zero, so it looks like I have COM3 and COM4 disabled on this system.

9.6.5 See Also

man dmesg
man devinfo
man netstat
man kenv

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