Peter Stuge <[EMAIL PROTECTED]> writes: > On Fri, Dec 01, 2006 at 11:19:16AM -0800, Greg KH wrote: >> Well, earlyprintk will not work, as you need PCI up and running. > > Not all of it though. LinuxBIOS will probably do just enough PCI > setup to talk to the EHCI controller and use the debug port _very_ > soon after power on.
Right. For LinuxBIOS not a problem for earlyprintk in the kernel somethings might need to be refactored. The challenge in the kernel is we don't know at build to how to do a pci_read_config... The other hard part early in the kernel is the fact that the bar is memory mapped I/O. Which means it will need to get mapped into the kernels page tables. >> And I have some code that barely works for this already, perhaps >> Eric and I should work together on this :) > > I would be interested in having a look at any code for it too. Sure, I will send it out shortly. I currently have a working user space libusb thing (easy, but useful for my debug) and a rude read/write to the bar from user space program that allowed me to debug the worst of the state machine from user space. I don't think I have the state setup logic correct yet but that is minor in comparison. I really wish the EHCI spec had made that stupid interface 16 bytes instead of 8 or had a way to chain multiple access together. The we could have used a normal usb cable. As it is most descriptors are 1 byte to big to read. >> Yes, that will work just fine today using the usb-serial generic >> driver. > > Ugh. I did not know it was that generic. The irony is that I always > ask other libusb users to check the kernel drivers to see if they > really need to write a libusb app. > > >> I'll knock up a "real" driver for the device later today and send >> it to Linus, as it's trivial to do so, and will make it simpler >> than using the module parameters. > > Awesome. Thanks! Yep. It looks like it sufficient generic. The Maximum packet size appears to be reported correctly for writes which is the tidbit I was worried about but otherwise it is just a pair of bulk transfer endpoints. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
