Linux lPCI IDs: Unknown Device Issue

lspci is a utility for displaying information about PCI buses in the system and devices connected to them. The list of PCI IDs that lspci uses is contained in /usr/share/hwdata/pci.ids file.It might occur that the PCI id of a given device is not contained in that file. In that case, lspci will print out 'Unknown device' with the PCI id. To resolve this issue the pci.ids file must be updated or modified to include the missing ids.

In this example, we have a RedHat Linux EL5 installed as a virtual machine on VMware. The selected adapter type for the linux virtual machine is VMXNET3. If we run lspci on the Linux virtual machine, we get:

[root@localhost ~]# lspci
00:00.0 Host bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX Host bridge (rev 01)
00:01.0 PCI bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX AGP bridge (rev 01)
00:07.0 ISA bridge: Intel Corporation 82371AB/EB/MB PIIX4 ISA (rev 08)
00:07.1 IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)
00:07.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 08)
00:07.7 System peripheral: VMware Inc Unknown device 0740 (rev 10)
00:0f.0 VGA compatible controller: VMware Inc [VMware SVGA II] PCI Display Adapter
00:10.0 SCSI storage controller: LSI Logic / Symbios Logic 53c1030 PCI-X Fusion-MPT Dual Ultra320 SCSI (rev 01)
00:11.0 PCI bridge: VMware Inc Unknown device 0790 (rev 02)
00:15.0 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:15.1 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:15.2 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:15.3 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:15.4 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:15.5 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:15.6 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:15.7 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.0 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.1 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.2 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.3 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.4 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.5 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.6 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:16.7 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.0 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.1 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.2 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.3 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.4 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.5 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.6 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:17.7 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.0 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.1 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.2 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.3 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.4 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.5 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.6 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)
00:18.7 PCI bridge: VMware Inc Unknown device 07a0 (rev 01)

03:00.0 Ethernet controller: VMware Inc Unknown device 07b0 (rev 01)

In the above example, devices with ids 07a0 and 07b0 are unknown. Indeed in the pci.ids file, under VMware Inc we have the following:

15ad  VMware Inc
        0405  [VMware SVGA II] PCI Display Adapter
        0710  Virtual SVGA
        0720  VMware High-Speed Virtual NIC [vmxnet]

/usr/share/hwdata/pci.ids file must be modified as follows:

15ad  VMware

0405  SVGA II Adapter

0710  SVGA Adapter

0720  VMXNET Ethernet Controller

0740  Virtual Machine Communication Interface

0770  USB2 EHCI Controller

0774  USB1.1 UHCI Controller

0778  USB3 xHCI Controller

0790  PCI bridge

07a0  PCI Express Root Port

07b0  VMXNET3 Ethernet Controller

07c0  PVSCSI SCSI Controller

0801  Virtual Machine Interface

15ad 0800  Hypervisor ROM Interface

1977  HD Audio Controller

After the modification, lspci gives the follwoing:

[root@localhost ~]# lspci
00:00.0 Host bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX Host bridge (rev 01)
00:01.0 PCI bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX AGP bridge (rev 01)
00:07.0 ISA bridge: Intel Corporation 82371AB/EB/MB PIIX4 ISA (rev 08)
00:07.1 IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)
00:07.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 08)
00:07.7 System peripheral: VMware Virtual Machine Communication Interface (rev 10)
00:0f.0 VGA compatible controller: VMware SVGA II Adapter
00:10.0 SCSI storage controller: LSI Logic / Symbios Logic 53c1030 PCI-X Fusion-MPT Dual Ultra320 SCSI (rev 01)
00:11.0 PCI bridge: VMware PCI bridge (rev 02)
00:15.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.7 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.7 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.7 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.7 PCI bridge: VMware PCI Express Root Port (rev 01)

03:00.0 Ethernet controller: VMware VMXNET3 Ethernet Controller (rev 01)

Socket Buffer Size

In network programming, we usually set the a buffer size to the sockets using the SO_RCVBUF and SO_SNDBUF socket options. In the code, we use the setsockopt function as follows:

int sockfd;                                     /* Socket descriptor */
int SockInBuffSize = 1024 * 512;  /* Size of the input socket buffer here 262144 bytes*/

setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &SockInBuffSize, sizeof(SockInBuffSize));

For the above code to work, we need to make sure that the OS will allow us to set larger socket buffer sizes. We can achieve this using sysctl command as follows:

#sysctl -w net.core.rmem_max=524288 
#sysctl -w net.core.wmem_max=524288 
#sysctl -w net.core.wmem_default=524288 
#sysctl -w net.core.rmem_default=524288

Where rmem is the receive buffer and wmem the send buffer.

Failing to do the above, results in the socket buffer sizes that cannot be greater than the max values defined in /proc/net/core/

To view the current values of socket buffer sizes use the following command:

#sysctl -a | grep net.core

References

Working with NIC Ring Buffers
This post explains how to modify the NIC ring buffers which are important in fine tuning your network performance.
Source: www.scottalanmiller.com

Resolving Common Queuing/Frame Loss Issues
This chapter of Linux RedHat document explains how to use ethtool to fine tune your NIC for better network performance.
Source: redhat.com

Find the Network Device Vendor ID (VID)

First find the devices that are connected to the all PCI buses in your system

# lspci

The output should be something similar to:

00:00.0 Host bridge: Intel Corporation X58 I/O Hub to ESI Port (rev 13)

00:01.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 1 (rev 13)

00:02.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 2 (rev 13)

00:03.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 3 (rev 13)

00:04.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 4 (rev 13)

00:05.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 5 (rev 13)

00:06.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 6 (rev 13)

00:07.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 7 (rev 13)

00:08.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 8 (rev 13)

00:09.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 9 (rev 13)

00:0a.0 PCI bridge: Intel Corporation X58 I/O Hub PCI Express Root Port 10 (rev 13)

00:0d.0 Host bridge: Intel Corporation Unknown device 343a (rev 13)

00:0d.1 Host bridge: Intel Corporation Unknown device 343b (rev 13)

00:0d.2 Host bridge: Intel Corporation Unknown device 343c (rev 13)

00:0d.3 Host bridge: Intel Corporation Unknown device 343d (rev 13)

00:0d.4 Host bridge: Intel Corporation X58 Physical Layer Port 0 (rev 13)

00:0d.5 Host bridge: Intel Corporation Quickpath Interconnect Physical Layer Port 1 (rev 13)

00:0d.6 Host bridge: Intel Corporation Unknown device 341a (rev 13)

00:0e.0 Host bridge: Intel Corporation Unknown device 341c (rev 13)

00:0e.1 Host bridge: Intel Corporation Unknown device 341d (rev 13)

00:0e.2 Host bridge: Intel Corporation Unknown device 341e (rev 13)

00:0e.3 Host bridge: Intel Corporation Unknown device 341f (rev 13)

00:0e.4 Host bridge: Intel Corporation Unknown device 3439 (rev 13)

00:14.0 PIC: Intel Corporation X58 I/O Hub System Management Registers (rev 13)

00:14.1 PIC: Intel Corporation X58 I/O Hub GPIO and Scratch Pad Registers (rev 13)

00:14.2 PIC: Intel Corporation X58 I/O Hub Control Status and RAS Registers (rev 13)

00:1d.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #1

00:1d.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #2

00:1d.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #3

00:1d.3 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #6

00:1d.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #1

00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 90)

00:1f.0 ISA bridge: Intel Corporation 82801JIB (ICH10) LPC Interface Controller

00:1f.2 IDE interface: Intel Corporation 82801JI (ICH10 Family) 4 port SATA IDE Controller

01:03.0 VGA compatible controller: ATI Technologies Inc ES1000 (rev 02)

01:04.0 System peripheral: Compaq Computer Corporation Integrated Lights Out Controller (rev 03)

01:04.2 System peripheral: Compaq Computer Corporation Integrated Lights Out  Processor (rev 03)

01:04.4 USB Controller: Hewlett-Packard Company Proliant iLO2 virtual USB controller

01:04.6 IPMI SMIC interface: Hewlett-Packard Company Proliant iLO2 virtual UART

02:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)

02:00.1 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)

03:00.0 RAID bus controller: Hewlett-Packard Company Smart Array G6 controllers (rev 01)

The network adapters found in the above output are highlighted in yellow. In this particular case it is two Broadcom Ethernet controllers. To get the Vendor ID (VID) and the Device ID (DID) of these controllers, use the following command:

# lspci -n | grep x:x

The output is:

00:00.0 0600: 8086:3406 (rev 13)

00:01.0 0604: 8086:3408 (rev 13)

00:02.0 0604: 8086:3409 (rev 13)

00:03.0 0604: 8086:340a (rev 13)

00:04.0 0604: 8086:340b (rev 13)

00:05.0 0604: 8086:340c (rev 13)

00:06.0 0604: 8086:340d (rev 13)

00:07.0 0604: 8086:340e (rev 13)

00:08.0 0604: 8086:340f (rev 13)

00:09.0 0604: 8086:3410 (rev 13)

00:0a.0 0604: 8086:3411 (rev 13)

00:0d.0 0600: 8086:343a (rev 13)

00:0d.1 0600: 8086:343b (rev 13)

00:0d.2 0600: 8086:343c (rev 13)

00:0d.3 0600: 8086:343d (rev 13)

00:0d.4 0600: 8086:3418 (rev 13)

00:0d.5 0600: 8086:3419 (rev 13)

00:0d.6 0600: 8086:341a (rev 13)

00:0e.0 0600: 8086:341c (rev 13)

00:0e.1 0600: 8086:341d (rev 13)

00:0e.2 0600: 8086:341e (rev 13)

00:0e.3 0600: 8086:341f (rev 13)

00:0e.4 0600: 8086:3439 (rev 13)

00:14.0 0800: 8086:342e (rev 13)

00:14.1 0800: 8086:3422 (rev 13)

00:14.2 0800: 8086:3423 (rev 13)

00:1d.0 0c03: 8086:3a34

00:1d.1 0c03: 8086:3a35

00:1d.2 0c03: 8086:3a36

00:1d.3 0c03: 8086:3a39

00:1d.7 0c03: 8086:3a3a

00:1e.0 0604: 8086:244e (rev 90)

00:1f.0 0601: 8086:3a18

00:1f.2 0101: 8086:3a20

01:03.0 0300: 1002:515e (rev 02)

01:04.0 0880: 0e11:b203 (rev 03)

01:04.2 0880: 0e11:b204 (rev 03)

01:04.4 0c03: 103c:3300

01:04.6 0c07: 103c:3302

02:00.0 0200: 14e4:1639 (rev 20)

02:00.1 0200: 14e4:1639 (rev 20)

03:00.0 0104: 103c:323a (rev 01)

The Vendor ID (VID) and Device ID (DID) are highlighted in green. In the above output VID=14e4 and DID=1639.

References

• PCIdatabase.com

You can find here PCI vendor list by name or by device ID, and other resources on the PCI bus.

Source: www.pcidatabase.com

• lspci(8) - Linux man page

• PCI configuration space

Configuring the Flow Control

If a node on an Ethernet network sends packets faster than the receive node can handle, then the overwhelmed node can send pause frame to the sender pausing the sender for a short time. This process is called Flow Control.

If for any reason Flow Control is undesired it can be disabled using the ethtool. The example below is applied to the Intel e1000.

To list current status of flow control on the eth0 device, run the following command:

#ethtool –a eth0

The output:

Pause parameters for eth0:
Autonegotiate: on
RX: on
TX: on

To disable the Flow Control on the Tx and Rx, you need first to disable the auto-negotiations:

# ethtool --pause eth0 autoneg off

Then we need to disable the Flow Control for the send and receive traffic:

# ethtool --pause tx off rx off

Check again the status of Flow Control. All fields should be set to off:

# ethtool –a eth0
Pause parameters for eth0:
Autonegotiate: off
RX: off
TX: off

References

Ethernet flow control
Source: http://en.wikipedia.org

Find the Network Driver Version

Use the 'ethtool' command line as follows:

#ethtool -i eth0

The output should be something similar to the following:

driver: bnx2

version: 1.7.9-1

firmware-version: 4.6.4 NCSI 1.0.3

bus-info: 0000:02:00.0

Note the buf-info value of 02:00.0. Using that value with the lspci command, we can learn more on the vendor and type of the Ethernet device

#lspci | grep 02:00.0

02:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)

In conclusion, bnx2 is the Broadcom in-kernel Linux driver for the NetXtreme II 1G Ethernet device.

Linux OS installed in 32-bit or 64-bit?

You can use the getconf linux command as follows:

$ getconf LONG_BIT

the will return the Number of bits in a type long int. If the value is 32 then you have a 32-bit Linux OS, otherwise it is a 64-bit OS

References

• getconf(1) - Linux man page (source: linux.die.net)
• getconf Command (source: IBM AIX documentation)
• How can we find out if the Linux OS installed is 32-bit or 64-bit? (source: www.redhat.com)

Apache Server Files Permissions

Files permissions on the Apache server is tightly linked with two configuration parameters in the Apache server configuration file (httpd.conf).  These are the User and Group configuration parameters that set the (User ID) UID and (Group ID) GID of the httpd binary. In the default configuration file (default /etc/httpd/conf/httpd.conf in RedHat Linux) we have following:    

#
# If you wish httpd to run as a different user or group, you must run
# httpd as root initially and it will switch.
#
# User/Group: The name (or #number) of the user/group to run httpd as.
#  . On SCO (ODT 3) use "User nouser" and "Group nogroup".
#  . On HPUX you may not be able to use shared memory as nobody, and the
#    suggested workaround is to create a user www and use that user.
#  NOTE that some kernels refuse to setgid(Group) or semctl(IPC_SET)
#  when the value of (unsigned)Group is above 60000;
#  don't use Group #-1 on these systems!
#
User apache
Group apache

In the above configuration, the User and Group are set to 'apache'. The httpd binary should start as root, since only a root user can change the user and group in runtime. httpd binary as user 'root' binds to port 80 (443 for https), or to an alternative port defined in the configuration file. Then, it creates child processes with the User and Group as defined in the configuration file. Running the service httpd, and listing the httpd processes we have:

[root@localhost ~]# ps -ef | grep httpd
root     22680     1  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22682 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22683 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22684 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22685 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22686 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22687 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22688 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd
apache   22689 22680  0 11:19 ?        00:00:00 /usr/sbin/httpd

and we have the following open tcp port:

[root@localhost ~]# netstat -na -tcp | grep httpd
tcp        0      0 :::80                       :::*                        LISTEN      22680/httpd
tcp        0      0 :::443                     :::*                        LISTEN      22680/httpd

The above shows a httpd daemon process with pid 22680 running as root, and a number of child httpd processes running owned by the 'apache' user. This is common practice in the Apache configuration, since we do not want the child processes to have the same privileges as root. Apache documentation states that the configured user and group ('apache' in the above example), should not own any content on the server.

Let us check that a script run by the httpd daemon has 'apache' user id. The following perl script is used, and placed /var/www/cgi-bin folder (default configuration):

#!/usr/bin/perl
my $whoiami=`whoami`;
print "\n$whoiami";
exit

Running this script from the web browser gives:

apache

The above means that the process that run this script on the Apache server is owned by 'apache'. This is in concordance with the configuration file we have.

cgi-scripts file permissions

Looking at the file permission of the Perl script file, we have:

[root@localhost cgi-bin]# ls -l -rwxr-xr-x 1 root   root   124 Oct 31 11:50 test.pl

This shows that the file is owned by root, and is part of the root group. The owner has read-write-execute privileges. The group and all users have read-execute privileges. Usually, we want server users to be able to modify script files without having 'root' privileges. Also, we need to disable read and execute privileges of the all users. We achieve this by using groups. Lets assume we want the user 'Alice' to be able to edit this file. For this purpose, we create a group 'webcontent' and add user 'Alice' to this group as follows:

[root@localhost]# groupadd webcontent

We need to add the 'apache' user to the 'webcontent' group as well, because the user 'apache' needs to be able to run this script

[root@localhost]# usermod -G web-content alice
[root@localhost]# usermod -G web-content apache

Now we need to set the correct permissions to the script file:

[root@localhost cgi-bin]# chmod 750 test.pl

If for any reason the script does not run, check Apache server error log file. If you notice something like the following:

[Fri Nov 01 10:24:11 2013] [error] [client xxx.xxx.xxx.xxx] (13)Permission denied: exec of '/var/www/cgi-bin/test.pl' failed

then the file permissions are set wrong for the given script. Review the steps above and set your file permission correctly.

References

Apache Tutorial: Dynamic Content with CGI

File and Directory Ownership and Permissions for Web Content

Learn Linux, 101: Manage file permissions and ownership