Hello,
I am testing my special modems with Redhat 7.2 in Dell Pentium3 PC which has
a built-in USB host. When I put two modem in the two built-in USB port, the
modems can both reach up to the maximum speed 384kb/s. Because I need to
test more than 2 modems, so I used a USB1.1 hub. However, the hub can only
support upto 2 modem at 384kb/s. When more than 2 modem used, the throughput
reduces dramatically.
If the hub is at USB full speed, it should support up to 12Mb/s. That is
more than two modems. Looks like it is running at low speed in my case.
Anyone knows what determines the speed of the USB host/hub?
The following is my /proc/bus/usb/devices:
(I changed vendorID, productID, manufacturor and product to xxxx)
T: Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2
B: Alloc= 11/900 us ( 1%), #Int= 1, #Iso= 0
D: Ver= 1.00 Cls=09(hub ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1
P: Vendor=0000 ProdID=0000 Rev= 0.00
S: Product=USB UHCI Root Hub
S: SerialNumber=dce0
C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr= 0mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub
E: Ad=81(I) Atr=03(Int.) MxPS= 8 Ivl=255ms
T: Bus=01 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#= 10 Spd=12 MxCh= 4
D: Ver= 1.10 Cls=09(hub ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1
P: Vendor=0451 ProdID=2046 Rev= 1.25
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub
E: Ad=81(I) Atr=03(Int.) MxPS= 1 Ivl=255ms
T: Bus=01 Lev=02 Prnt=10 Port=01 Cnt=01 Dev#= 11 Spd=12 MxCh= 0
D: Ver= 1.01 Cls=02(comm.) Sub=00 Prot=00 MxPS=16 #Cfgs= 1
P: Vendor=xxxx ProdID=xxxx Rev= 0.00
S: Manufacturer=xxxxxx
S: Product=xxxx
S: SerialNumber=Serial Number
C:* #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=acm
E: Ad=81(I) Atr=03(Int.) MxPS= 16 Ivl= 32ms
I: If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=acm
E: Ad=8a(I) Atr=02(Bulk) MxPS= 64 Ivl= 0ms
E: Ad=0b(O) Atr=02(Bulk) MxPS= 64 Ivl= 0ms
Thanks a lot.
Simon
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