Why Core processor PCIe Root port absent until device attach
Posted: Tue Nov 13, 2012 8:50 pm
Dear all,
I have one question about the behavior of v2/3rd Gen Core processor PCI Express Root Port - 0155 ( where 0155 is the device id for this root port in Intel platform...)
@ platform information:
- OS: Win7 Pro 32bit
- MB: ASUS P8 Z77 VLE Plus
- CPU : Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
@ phenomenon:
- if one PCIe device is attached(plug) to PCI Express slot 5, then I can see "...v2/3rd Gen Core processor PCI Express Root Port - 0155" in [Device Manager].
- But if no device plug into slot 5, then this root port is absent in [Device Manager]
@ My questions are:
(1) why this root port is "disabled" without device attached ? ( for other pcie root ports, I found it is still present in [Device Manager] even though no device attached ! )
Can I enable it manually in Ex. DOS ?
(2) how to absolutely identify PCIe root port ?
Ex. PCIe root port is the PCI device in which:
a. class code is 0x6( bridge device)
b. PCIe capability exist
Am I correct ?
Thanks !
I have one question about the behavior of v2/3rd Gen Core processor PCI Express Root Port - 0155 ( where 0155 is the device id for this root port in Intel platform...)
@ platform information:
- OS: Win7 Pro 32bit
- MB: ASUS P8 Z77 VLE Plus
- CPU : Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
@ phenomenon:
- if one PCIe device is attached(plug) to PCI Express slot 5, then I can see "...v2/3rd Gen Core processor PCI Express Root Port - 0155" in [Device Manager].
- But if no device plug into slot 5, then this root port is absent in [Device Manager]
@ My questions are:
(1) why this root port is "disabled" without device attached ? ( for other pcie root ports, I found it is still present in [Device Manager] even though no device attached ! )
Can I enable it manually in Ex. DOS ?
(2) how to absolutely identify PCIe root port ?
Ex. PCIe root port is the PCI device in which:
a. class code is 0x6( bridge device)
b. PCIe capability exist
Am I correct ?
Thanks !