Hello Alan, At Sun, Jul 10, 2005 at 04:36:17PM -0400, Alan Stern wrote: > > - it works when directly attached to the PC > > - it doesn't work when attached to an external USB hub > > - it does work again when I remove ehci-hcd > Do you know if the camera uses isochronous transfers? You can tell if > there are any iso endpoints by looking at the camera's entry in > /proc/bus/usb/devices.
I'd think so, it has "Atr=01(Isoc)" all over the place: T: Bus=01 Lev=02 Prnt=05 Port=03 Cnt=01 Dev#= 6 Spd=12 MxCh= 0 D: Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 P: Vendor=0c45 ProdID=6005 Rev= 1.01 S: Product=USB camera C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=500mA I: If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=sn9c102 E: Ad=81(I) Atr=01(Isoc) MxPS= 0 Ivl=1ms E: Ad=82(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms E: Ad=83(I) Atr=03(Int.) MxPS= 1 Ivl=100ms I: If#= 0 Alt= 1 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=sn9c102 E: Ad=81(I) Atr=01(Isoc) MxPS= 128 Ivl=1ms E: Ad=82(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms E: Ad=83(I) Atr=03(Int.) MxPS= 1 Ivl=100ms (cut 7 more entries alike). > The symptoms you described are typical for IN iso transfers. The ehci-hcd > driver has incomplete support for such transfers when they come from a > full-speed device attached via a high-speed hub. The work-arounds are: > attach the device directly to the PC (as you know), rmmod ehci-hcd (as you > know), or use a USB 1.1 hub instead of a USB 2.0 hub. OK, that helps a lot. Looking through the kernel config, I now understand the "full speed ISO transactions" a bit more :) I'll look for an USB1.1 hub somewhere (or wait for the kernel implementation). Thanks so far! Best regards, Valentijn -- http://www.openoffice.nl/ Open Office - Linux Office Solutions Valentijn Sessink [EMAIL PROTECTED]
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