On Tue, 22 Oct 2002, Reid Thompson wrote:

| contents of /proc/bus/usb/devices.  The device of interest is the Topaz
| HID Tablet ( between the double lines)
|
...
| =====================================================
| T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  7 Spd=1.5 MxCh= 0
| D:  Ver= 1.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
| P:  Vendor=06a8 ProdID=0043 Rev= 1.01
| S:  Manufacturer=Topaz
| S:  Product=Topaz HID Tablet
| C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA
| I:  If#= 0 Alt= 0 #EPs= 2 Cls=03(HID  ) Sub=00 Prot=00 Driver=hid
| E:  Ad=81(I) Atr=03(Int.) MxPS=   8 Ivl=  1ms
| E:  Ad=02(O) Atr=03(Int.) MxPS=   8 Ivl=  1ms
| =====================================================
...

The device's endpoints use 1 ms intervals.
You didn't say which host controller driver you are using...
Also what kernel version is it?

I don't know much about evdev/hiddev.  Does anyone know if
they have their own device/endpoint polling intervals?

~Randy

| Randy.Dunlap wrote:
|
| >On Tue, 22 Oct 2002, Reid Thompson wrote:
| >
| >| Is there a means to alter the read frequency for hiddev/evdev devices?
| >| I have an HID device that outputs at 1ms intervals and, after some
| >| research, it appears that evdev & maybe hiddev are read at 2ms
| >| intervals????  I am getting what appears to be bad data from the hiddev
| >| device -- could it be that my device is overwriting data before it is
| >| being read due to this discrepancy in timing?  The device works fine as
| >| a HID device on windows.
| >| _______________________________________________
| >
| >The read frequency comes from the device endpoint's "interval"
| >parameter.  Is that value set to 1 ms?  The value is listed
| >for each endpoint in /proc/bus/usb/devices.
| >You could post the contents of that file when your device is
| >attached.
| >
| >You can always modify the Linux source code so that it uses
| >a different interval for a specific device if that's what
| >you need to do.  Of course, that only helps in your location,
| >not other people who are using that device with Linux.
| >
| >Also, which host controller driver are you using?
| >I haven't kept up with them very closely, but I guess there could
| >be some issue with one of them not supporting 1 ms intervals...
| >That wouldn't be good.



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