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). > > 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. > > Are you using CF too, or an other disk in PIO mode ? > > PIO mode access will generate quite some CPU load in kernel mode, > it seems that the kernel doesn't serve the USB stuff fast enough. > In my application I don't care if some frames get lost or damaged. > But the halting of the camera is not acceptable. > > greetings, > Rob van Nieuwkerk > > Sysinfo: > -------- > 300MHz Geode GX1 (= Pentium compatible CPU) > various 2.4.x kernels > PCVC740K webcam > pwc compressor > OHCI > > > ------------------------------------------------------- > This SF.Net email sponsored by: Free pre-built ASP.NET sites including > Data Reports, E-commerce, Portals, and Forums are available now. > Download today and enter to win an XBOX or Visual Studio .NET. > http://aspnet.click-url.com/go/psa00100006ave/direct;at.asp_061203_01/01 > _______________________________________________ > [EMAIL PROTECTED] > To unsubscribe, use the last form field at: > https://lists.sourceforge.net/lists/listinfo/linux-usb-devel > ------------------------------------------------------- This SF.Net email sponsored by: Free pre-built ASP.NET sites including Data Reports, E-commerce, Portals, and Forums are available now. Download today and enter to win an XBOX or Visual Studio .NET. http://aspnet.click-url.com/go/psa00100006ave/direct;at.asp_061203_01/01 _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
