interrupt driven device giving erroneous packets

Hello ,

i made an USB function driver for a touch screen controller .
the controller is a simple interrupt driven device .
at the moment im only geting data packets from the controller and im not
using them .(just displaying them with debuging tools)
i tested my driver on several computer and i got some weird behavior on a P3
1ghz running a windows home edition .
when i move quickly my finger on the touch screen , a lot of junk packet
appears .
when i make smooth moves , data are corrects though .
anyone would have any idea why i’m geting wrong packet through an interrupt
pipe ?

i could filter those packets but i’d like to know why those appears .

the computer is a small desktop with integrated video / network . all INTEL
chips ( 815 familly)
on a MSI mb .

any advice would be greatly appreciated :wink:
thanks

Ronan

Things I would do:

  1. check the MS knowlegde base for ‘815 usb’.
  2. Hook up a USB Analyser (CATC preferred :slight_smile: ). Check the raw data.
  3. Check your URB buffer handling. Maybe you are using
    the same buffer in different (concurrent) reads.
    Norbert.

“The best defensive driving system I have found to date is a passenger
leaning out the window with a shotgun.”
---- snip ----

i made an USB function driver for a touch screen controller .
the controller is a simple interrupt driven device .
at the moment im only geting data packets from the controller and im not
using them .(just displaying them with debuging tools)
i tested my driver on several computer and i got some weird behavior on a P3
1ghz running a windows home edition .
when i move quickly my finger on the touch screen , a lot of junk packet
appears .
when i make smooth moves , data are corrects though .
anyone would have any idea why i’m geting wrong packet through an interrupt
pipe ?

i could filter those packets but i’d like to know why those appears .

the computer is a small desktop with integrated video / network . all INTEL
chips ( 815 familly)
on a MSI mb .
---- snip ----