On Tue, Feb 08, 2005 at 11:48:11AM -0800, David Brownell wrote: > On Tuesday 08 February 2005 11:05 am, Andi Kleen wrote: > > My plan was to just drive a normal host2host cable through > > debug port. It'll need some hacks, but should not be too bad. > > I'd have expected some of them to _be_ "debug devices" in fact, > but I'm not sure how common that is. My extremely limited sample > shows no success there ... they didn't have debug descriptors.
Just debug port should work even without debug descriptors, shouldn't it? (with some manual scanning of addresses) > > On Tue, Feb 08, 2005 at 10:11:25AM -0800, David Brownell wrote: > > > > It's annoying > > > > to have to fight against such dumb code in the kernel then. > > > > > > Do you actually have a debug port driver for Linux? And some > > > hardware that it can talk to? > > > > Not yet. But I have(had) plans to write one. Unfortunately > > it dropped back a bit on the todo list, so not too much has happened > > yet:/ > > I have the untested guts of one ... attached, purely FYI. Adds > a couple KBytes of object code, and doesn't care if IRQs or DMA > are working (obviously). Thanks. > > > > > I started looking at that issue a while back: > > > > > > - What model to use for it? OK, "console" for output is > > > at least a (unidirectional) start; how about remote GDB? > > > > Not sure I understand the q. (model?) My plan was to start with output > > only, and then later implement receiving too. > > The question is how to _use_ the port. What data to write to > it (console data? binary event records?), or read from it. > It's a bidirectional channel, so more featureful models are > possible, like GDB stubs for debug-as-target. Just ordinary ASCII console data. Other protocols like kgdb can run over that fine. In fact the kgdb remote protocol is ASCII based. > No; but that gets back to the model question. My assumption > was that something simple should work: if the port is in use > by the debug channel when EHCI starts, then ignore it from > then on ... or at least, until the debug port driver drops it. Yes, obviously when a debug device is plugged in the port shouldn't be used by the normal drivers (ignoring hubs here, I think not supporting them is not a issue for debugging) -Andi ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
