On Wednesday 09 January 2008, topo gigio wrote: > LoL, > well thanks to all for your answers, it's funny > that's a power problem,
So ... did you verify that not using the external power supply *was* causing the problem? > But... if, like u say, this is a power problem, why > the same device (a stupid lexar usb pen drive) work > whitout problems under windows? (Well i must verify if > it really works at 2.0) Does it work at high speed in MS-Windows, using the same hardware configuration? > And why, if i use only the ohci driver, all works well > in linux, with usb 1.1 speed (i don't know if usb 1.1 > require less power than usb 2.0)? In this case I can only report what I observed: that EHCI in a CardBus format needed extra power. > Ok, googling around, i found this "Transmitted signal > levels are 0.0–0.3 volts for low and 2.8–3.6 volts for > high in Full Speed and Low Speed modes, and +-400mV in > High Speed (HS) mode." > Ok, power vary if different speed is selected, Actually Voltage != power, but it is one factor that affects power usage. (See a basic electronics book for details.) > but > isn't possible to add a feauture to ehci module to > auto select lower speed if there isn't enought power > to reach th HighSpeed mode? I've not heard of any way to detect there's not enough power being provided to a CardBus device. Maybe there's some way through the PCMCIA framework, but I'd suspect there is none. After all, it's just presented as another PCI card. And if there were such a feature available I would expect the PMCIA framework would implement it; the EHCI driver only knows about EHCI, not PCMCIA. > I think that's usefull for a lot of unskilled people > that don't know how to compile a kernel to workaroud > this problem. If that really *is* the solution to your problem, I'd be very surprised if the manufacturer of your card did not provide stern warnings about using the external power supply all over the box and throughout the printed documentation. This isn't a software issue at all. > If u want i can spend my time as beta tester, i > haven't required programming skill to do it myself. First thing to test and report: did my suggestion actually solve your problem? - Dave > Best regards > > > --- David Brownell <[EMAIL PROTECTED]> wrote: > > > On Tuesday 08 January 2008, topo gigio wrote: > > > module, last week i had bought an pcmcia carbus > > > card > > > with usb 2.0 and firewire ports based on ALi > > > chipset. > > > If i use only the ohci driver, all ports goes well > > > and > > > i can use it without problems (but as usb 1.1). > > > When i use the ehci driver, i can't mount any pen > > > drive or something like that. > > > > As Alan pointed out, you're getting fault codes > > which indicate electical trouble. > > > > Most Cardbus adapters like that one come with an > > external power supply, since not much power is > > available through the PCMCIA connector. Were you > > providing enough power to the card? > > > > - Dave > > > - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
