Hi.
I have a IBM thinkpad T40 laptop. It has one usb root-hub with 2 ports. I ran 'lspci' command on my machine and got the following output.
:01.0 PCI bridge: Intel Corp. 82855PM Processor to AGP Controller (rev 03)
00:1d.0 USB Controller: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHC
I Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHC
I Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHC
I Controller #3 (rev 01)
00:1d.7 USB Controller: Intel Corp. 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controll
er (rev 01)
00:1e.0 PCI bridge: Intel Corp. 82801 Mobile PCI Bridge (rev 81)
00:1f.0 ISA bridge: Intel Corp. 82801DBM (ICH4-M) LPC Interface Bridge (rev 01)
00:1f.1 IDE interface: Intel Corp. 82801DBM (ICH4-M) IDE Controller (rev 01)
00:1f.3 SMBus: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) SMBus Controller
(rev 01)
00:1f.5 Multimedia audio controller: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/IC
H4-M) AC'97 Audio Controller (rev 01)
00:1f.6 Modem: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Modem Cont
roller (rev 01)
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility M7 LW [R
adeon Mobility 7500]
02:00.0 CardBus bridge: Texas Instruments PCI1520 PC card Cardbus Controller (re
v 01)
02:00.1 CardBus bridge: Texas Instruments PCI1520 PC card Cardbus Controller (re
v 01)
02:01.0 Ethernet controller: Intel Corp. 82540EP Gigabit Ethernet Controller (Mo
bile) (rev 03)
02:02.0 Network controller: Intel Corp. PRO/Wireless LAN 2100 3B Mini PCI Adapte
r (rev 04)
According to this information, I should have 4 USB root hubs since I have 4 USB host controllers. But I only have only 1 USB root hub. What are 3 others controllers are used for?
Thanks in advance