我购买了瑞萨电子的 PCIe 1x USB 3.0 卡，型号为 µPD720201，可插入我的 Dell Optiplex 990 主板的 PCIe 1x 插槽。
卡片：http://am.renesas.com/products/soc/usb_assp/product/upd720201/index.jsp
木板：http://clascsg.uconn.edu/download/specs/O990.pdf
现在，我知道我买的卡是比我的插槽更新一代的 PCIe。直到购买后我才知道有多代 PCIe。不过，从我在网上找到的信息来看，新一代 PCIe 只是提高了传输速率。这让我相信我可能仍然可以使用我买的卡，但不能满负荷使用，这对我来说没问题！
因此问题在于该卡被我的计算机识别，如以下清单所示：
lspci -v
03:00.0 USB controller: Renesas Technology Corp. uPD720201 USB 3.0 Host Controller (rev 03) (prog-if 30 [XHCI])
Flags: bus master, fast devsel, latency 0, IRQ 18
Memory at e1000000 (64-bit, non-prefetchable) [size=8K]
Capabilities: [50] Power Management version 3
Capabilities: [70] MSI: Enable- Count=1/8 Maskable- 64bit+
Capabilities: [90] MSI-X: Enable+ Count=8 Masked-
Capabilities: [a0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [150] Latency Tolerance Reporting
Kernel driver in use: xhci_hcd
和
lsusb -v
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 3.00
bDeviceClass 9 Hub
bDeviceSubClass 0 Unused
bDeviceProtocol 3
bMaxPacketSize0 9
idVendor 0x1d6b Linux Foundation
idProduct 0x0003 3.0 root hub
bcdDevice 3.16
iManufacturer 3 Linux 3.16.0-45-generic xhci_hcd
iProduct 2 xHCI Host Controller
iSerial 1 0000:03:00.0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 31
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xe0
Self Powered
Remote Wakeup
MaxPower 0mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 9 Hub
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0 Full speed (or root) hub
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0004 1x 4 bytes
bInterval 12
bMaxBurst 0
Hub Descriptor:
bLength 12
bDescriptorType 42
nNbrPorts 4
wHubCharacteristic 0x0009
Per-port power switching
Per-port overcurrent protection
bPwrOn2PwrGood 10 * 2 milli seconds
bHubContrCurrent 0 milli Ampere
bHubDecLat 0.0 micro seconds
wHubDelay 0 nano seconds
DeviceRemovable 0x00
Hub Port Status:
Port 1: 0000.02a0 5Gbps power Rx.Detect
Port 2: 0000.02a0 5Gbps power Rx.Detect
Port 3: 0000.02a0 5Gbps power Rx.Detect
Port 4: 0000.02a0 5Gbps power Rx.Detect
Binary Object Store Descriptor:
bLength 5
bDescriptorType 15
wTotalLength 15
bNumDeviceCaps 1
SuperSpeed USB Device Capability:
bLength 10
bDescriptorType 16
bDevCapabilityType 3
bmAttributes 0x02
Latency Tolerance Messages (LTM) Supported
wSpeedsSupported 0x0008
Device can operate at SuperSpeed (5Gbps)
bFunctionalitySupport 3
Lowest fully-functional device speed is SuperSpeed (5Gbps)
bU1DevExitLat 0 micro seconds
bU2DevExitLat 0 micro seconds
Device Status: 0x0001
Self Powered
但是当我将某些东西插入卡的 USB 端口时，没有电源供应，并且计算机也无法识别任何连接的设备。
类似问题
2.0 卡可以在 1.0 PCI Express 插槽上使用吗？，
PCI Express x16 2.0 插槽是否可以与 PCI Express x16 3.0 显卡配合使用
和
将 PCI Express 3.0 显卡插入 PCI-E 1.0 x16 插槽
有答案说该卡应该可以正常工作，尽管我的插槽是第一代的。
那么是否有其他因素可能阻塞了 USB 端口？还是我有一张不向后兼容的特殊卡？