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#1
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USB 2.0 bandwidth bug in XP SP2?
I have received some complaints about their USB audio speaker/mic is not
working properly with their USB webcam. I did some tests and find there may be a bug in XP SP2 on how USB 2.0 (high-speed) bandwidth is handled, here is my configuration: - P4 2.26GHz XP SP2 PC with high-speed USB port. - D link USB 2.0 hub connect to the PC USB 2.0 port. - Logitech QuickCam Pro 4000 connected to one port on the hub.(full speed camera) - A USB audio device (with built-in mic and speaker) to one of port on the hub. - And make sure the USB mic and speaker is Windows’ default audio devices. - Run an application to make sure the camera is streaming video. - Run Windows Media Player to play a song on the USB audio speaker, most of the time Media Player gives an error message, says there is something wrong with the audio device. When I go to Device manager checked the USB bandwidth usages, I have noticed the camera is using 75% bandwidth, and USB audio mic/speaker could use 35% when both running(turn off the camera), and system reserves 12%. When a high speed USB camera is used, the XP shows USB bandwidth usage 399% ???(not a typo, it’s 399%). According to the USB 2.0 specification, the high-speed 2.0 hub and the host pc should be a high-speed link, and the high-speed hub should be able handle many full speed devices at the same time, not just one full speed camera. I also checked the HUB with a USB 2.0 analyzer which shows the link is high speed, then I’m suspecting is XP SP2 which may have flaws in handle USB 2.0 bandwidth allocation: 1. The 399% bandwidth usage seems wrong. 2. Other Windows driver, such as USBAudio driver may check the bandwidth base on not exceeding 100%. User may also see a message that says “Out of USB Bandwidth”. That sounds like a big problem, I thought there must be a KB to talk about this, but I could not find one. Have you seen this? any comments? Thanks! |
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#2
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USB 2.0 bandwidth bug in XP SP2?
Each port on the mobo/internal card in the computer can
handle up to 480 mbps [real life a little less] but you have connected everything to your hub on one port, all the USB connectors on the hub are sharing the power and the bandwidth. This is not a problem with low bandwidth devices such as mice, keyboards and even flash memory, but your video and audio need real-time through-put. Use the hub for less demanding devices and connect the camera and speakers to the computer directly, or get another hub that connects to another port on the mobo/computer. Be sure to get powered hubs. "Yibo" wrote in message ... |I have received some complaints about their USB audio speaker/mic is not | working properly with their USB webcam. | I did some tests and find there may be a bug in XP SP2 on how USB 2.0 | (high-speed) bandwidth is handled, here is my configuration: | - P4 2.26GHz XP SP2 PC with high-speed USB port. | - D link USB 2.0 hub connect to the PC USB 2.0 port. | - Logitech QuickCam Pro 4000 connected to one port on the hub.(full speed | camera) | - A USB audio device (with built-in mic and speaker) to one of port on the | hub. | - And make sure the USB mic and speaker is Windows' default audio devices. | - Run an application to make sure the camera is streaming video. | - Run Windows Media Player to play a song on the USB audio speaker, most of | the time Media Player gives an error message, says there is something wrong | with the audio device. | | When I go to Device manager checked the USB bandwidth usages, I have noticed | the camera is using 75% bandwidth, and USB audio mic/speaker could use 35% | when both running(turn off the camera), and system reserves 12%. | When a high speed USB camera is used, the XP shows USB bandwidth usage 399% | ???(not a typo, it's 399%). | | According to the USB 2.0 specification, the high-speed 2.0 hub and the host | pc should be a high-speed link, and the high-speed hub should be able handle | many full speed devices at the same time, not just one full speed camera. | | I also checked the HUB with a USB 2.0 analyzer which shows the link is high | speed, then I'm suspecting is XP SP2 which may have flaws in handle USB 2.0 | bandwidth allocation: | 1. The 399% bandwidth usage seems wrong. | 2. Other Windows driver, such as USBAudio driver may check the bandwidth | base on not exceeding 100%. | | User may also see a message that says "Out of USB Bandwidth". | | That sounds like a big problem, I thought there must be a KB to talk about | this, but I could not find one. | | Have you seen this? any comments? | | Thanks! | |
#3
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USB 2.0 bandwidth bug in XP SP2?
Jim,
Thank you for your response. What you suggested can resolve this problem, indeed I suggested our customers to just do that: plug the camera and usb audio device to a different USB port on the PC not all into one hub. But, my point is why need to do that? A high-speed hub should be able to handle multiple full speed device. I tried the same configuration on Windows Vista Beta build 5472, which works fine: the camera is using 4% while it capturing video, and the USB audio device capturing audio uses 1% usb bandwidth. It seems to me, this is a XP SP2 bug. Any thoughts? "Jim Macklin" wrote: Each port on the mobo/internal card in the computer can handle up to 480 mbps [real life a little less] but you have connected everything to your hub on one port, all the USB connectors on the hub are sharing the power and the bandwidth. This is not a problem with low bandwidth devices such as mice, keyboards and even flash memory, but your video and audio need real-time through-put. Use the hub for less demanding devices and connect the camera and speakers to the computer directly, or get another hub that connects to another port on the mobo/computer. Be sure to get powered hubs. "Yibo" wrote in message ... |I have received some complaints about their USB audio speaker/mic is not | working properly with their USB webcam. | I did some tests and find there may be a bug in XP SP2 on how USB 2.0 | (high-speed) bandwidth is handled, here is my configuration: | - P4 2.26GHz XP SP2 PC with high-speed USB port. | - D link USB 2.0 hub connect to the PC USB 2.0 port. | - Logitech QuickCam Pro 4000 connected to one port on the hub.(full speed | camera) | - A USB audio device (with built-in mic and speaker) to one of port on the | hub. | - And make sure the USB mic and speaker is Windows' default audio devices. | - Run an application to make sure the camera is streaming video. | - Run Windows Media Player to play a song on the USB audio speaker, most of | the time Media Player gives an error message, says there is something wrong | with the audio device. | | When I go to Device manager checked the USB bandwidth usages, I have noticed | the camera is using 75% bandwidth, and USB audio mic/speaker could use 35% | when both running(turn off the camera), and system reserves 12%. | When a high speed USB camera is used, the XP shows USB bandwidth usage 399% | ???(not a typo, it's 399%). | | According to the USB 2.0 specification, the high-speed 2.0 hub and the host | pc should be a high-speed link, and the high-speed hub should be able handle | many full speed devices at the same time, not just one full speed camera. | | I also checked the HUB with a USB 2.0 analyzer which shows the link is high | speed, then I'm suspecting is XP SP2 which may have flaws in handle USB 2.0 | bandwidth allocation: | 1. The 399% bandwidth usage seems wrong. | 2. Other Windows driver, such as USBAudio driver may check the bandwidth | base on not exceeding 100%. | | User may also see a message that says "Out of USB Bandwidth". | | That sounds like a big problem, I thought there must be a KB to talk about | this, but I could not find one. | | Have you seen this? any comments? | | Thanks! | |
#4
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USB 2.0 bandwidth bug in XP SP2?
If you connect a 3/4 inch garden hose to a faucet at 45 PSI
pressure and open the valve wide open, you'll get a maximum of say, 50 gallons a minute flow from a 25 foot hose. If you add 200 feet of 3/4 inch hose the flow will be reduced to maybe 5 gallons a minute. If you make a manifold from brass pipe (a hub) and connect five 3/4 inch 10 foot hoses you won't get 250 gallons total flow, you won't get even the 50 gallons, same sort of thing happens with electricity and USB, each port has a maximum rate, each device has a maximum rate, when you exceed the available "pipe capacity" you get broken and reduced flow of water or signals. Also, a computer has buffers and must process the data to get an output. If you empty the buffer with a fast processor, the buffer must fill up again before the signal will be output [watch streaming video load, there may be settings in your computer for buffers, virtual memory and CPU priority that are causing the problem. I can't say more than that. A hub can certainly handle input and output, but can't do more than the single hub that is in use on the mobo. "Yibo" wrote in message ... | Jim, | Thank you for your response. | What you suggested can resolve this problem, indeed I suggested our | customers to just do that: plug the camera and usb audio device to a | different USB port on the PC not all into one hub. | But, my point is why need to do that? A high-speed hub should be able to | handle multiple full speed device. | | I tried the same configuration on Windows Vista Beta build 5472, which works | fine: the camera is using 4% while it capturing video, and the USB audio | device capturing audio uses 1% usb bandwidth. | | It seems to me, this is a XP SP2 bug. | | Any thoughts? | | | "Jim Macklin" wrote: | | Each port on the mobo/internal card in the computer can | handle up to 480 mbps [real life a little less] but you have | connected everything to your hub on one port, all the USB | connectors on the hub are sharing the power and the | bandwidth. This is not a problem with low bandwidth devices | such as mice, keyboards and even flash memory, but your | video and audio need real-time through-put. | Use the hub for less demanding devices and connect the | camera and speakers to the computer directly, or get another | hub that connects to another port on the mobo/computer. | | Be sure to get powered hubs. | | | | "Yibo" wrote in message | ... | |I have received some complaints about their USB audio | speaker/mic is not | | working properly with their USB webcam. | | I did some tests and find there may be a bug in XP SP2 on | how USB 2.0 | | (high-speed) bandwidth is handled, here is my | configuration: | | - P4 2.26GHz XP SP2 PC with high-speed USB port. | | - D link USB 2.0 hub connect to the PC USB 2.0 port. | | - Logitech QuickCam Pro 4000 connected to one port on the | hub.(full speed | | camera) | | - A USB audio device (with built-in mic and speaker) to | one of port on the | | hub. | | - And make sure the USB mic and speaker is Windows' | default audio devices. | | - Run an application to make sure the camera is streaming | video. | | - Run Windows Media Player to play a song on the USB audio | speaker, most of | | the time Media Player gives an error message, says there | is something wrong | | with the audio device. | | | | When I go to Device manager checked the USB bandwidth | usages, I have noticed | | the camera is using 75% bandwidth, and USB audio | mic/speaker could use 35% | | when both running(turn off the camera), and system | reserves 12%. | | When a high speed USB camera is used, the XP shows USB | bandwidth usage 399% | | ???(not a typo, it's 399%). | | | | According to the USB 2.0 specification, the high-speed 2.0 | hub and the host | | pc should be a high-speed link, and the high-speed hub | should be able handle | | many full speed devices at the same time, not just one | full speed camera. | | | | I also checked the HUB with a USB 2.0 analyzer which shows | the link is high | | speed, then I'm suspecting is XP SP2 which may have flaws | in handle USB 2.0 | | bandwidth allocation: | | 1. The 399% bandwidth usage seems wrong. | | 2. Other Windows driver, such as USBAudio driver may check | the bandwidth | | base on not exceeding 100%. | | | | User may also see a message that says "Out of USB | Bandwidth". | | | | That sounds like a big problem, I thought there must be a | KB to talk about | | this, but I could not find one. | | | | Have you seen this? any comments? | | | | Thanks! | | | | | |
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