Hello, On Friday 04 July 2003 16:02, Detlef Schmicker \(Siebertz Electronic GmbH\) wrote: > Hoi Rob, > > yes you are right. I use a hard disk in PIO mode. I will use a flash disk > also. > > I can reproduce the problem the same way as you can. > > I think it is probably in the USB layer, but I am not sure, if the pwc > could not handle > the problem better than it does. I must not reload the pwc driver, I can > restart my application > and the cam is up again. > > Do you have experience with other webcams on the same system? > > How can we attack the problem. > > Detlef > > ----- Original Message ----- > From: "Rob van Nieuwkerk" <[EMAIL PROTECTED]> > To: "Detlef Schmicker (Siebertz Electronic GmbH)" > <[EMAIL PROTECTED]> > Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> > Sent: Friday, July 04, 2003 1:20 PM > Subject: Re: [linux-usb-devel] pwc stops if the system is loaded > > > > Hello, > > > > > > Kernel 2.4.20, 300MHz Goede GX1 CPU, OHCI USB > > > > > > I use pwc without compressor module and with Jave Media Framework > > > > > > If I load the system by loading a "big (500k)" file with vi, than the > > webcam > > > > stops. > > > > > > Sometimes I get a message in /var/log/messages: > > > Jul 4 17:01:38 linux kernel: pwc Iso frame 0 of USB has error -18 > > > > > > > > > but often I do not get any unusual message, but I have a stoped > > > webcam. > > > > Hi Detlef, > > > > I have a similar problem: I found out that accessing a CompactFlash > > in PIO mode to much will cause the pwc to stop working. It usually > > gives this kernel message: > > > > "pwc_isoc_handler() called with status -75 [Babble (bad cable?)]" > > > > The user process accessing the camera never returns from read(). > > Only removing the driver modules and re-inserting them will "solve" > > the problem. (this is not a solution because reloading en initializing > > the camera driver takes many seconds: I'm building a real-time image > > processing application).
Hmm, using an USB camera might not be the best solution (ie. I've found USB isn't that reliable with ISOC transfers and such, and random errors crop up quite often). > > > > The problem can be triggered instantaneously by doing a: > > > > cat /dev/hda > /dev/null > > > > I'm not sure but I suspect that the problem is in the USB layer and > > not in the Philips webcam driver. Partially. I agree that the PWC error handling could be better, but sometimes USB errors are transient and you don't want to return an error and close the device at every bit that has fallen over. I'm working on this, by only setting an error condition if a number of consecutive USB frame errors occur. - Nemosoft ------------------------------------------------------- This SF.Net email sponsored by: Parasoft Error proof Web apps, automate testing & more. Download & eval WebKing and get a free book. www.parasoft.com/bulletproofapps _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
