On Sat, Jun 27, 2009 at 12:10 AM, Xiaofan Chen<xiaof...@gmail.com> wrote: > On Fri, Jun 26, 2009 at 11:56 PM, Dominic<dominic.r...@gmx.de> wrote: > >> I've been investigating the Windows USB mess a little yesterday. Maybe >> someone can help fill in the uncertainties, here's what I have collected so >> far. >> >> o libusb-win32 is API compatible with libusb 0.1, but is capable of >> somethings that libusb 0.1 can't > > libusb-win32 has two development branches. libusb-win32 0.1 is > API compatible with libusb 0.1 and adds isochronous transfer > and asynchronous I/O support specific to Windows. > >> o libftdi apparently works with libusb-win32's API (see for example >> Freddie's post) > > Yes. > >> o libusb-win32 comes with 3 (maybe 4) backends >> - a libusb driver and a libusb filter driver (not sure if this >> differenciation is still correct) >> - a HID backend (I've seen something like that with Keil's ULINK I guess, >> which looks like a HID to Windows, and thus needs no driver) >> - a WinUSB backend > > This is libusb-win32 1.0 branch. Unfortunately it is not working yet and I > do not know when the author will get time to get it working. Several people > suggested WinUSB backend to fix Vista 64 issues. I suggested the > HID backend since there are issues to use libusb-win32 with HID device. > >> o libusb-win32's drivers are supposed to be a dead end because they wont >> work with 64-bit windows (and probably not with Windows 7), but they do work >> for >> older versions that don't have WinUSB support (particularly 2000... leaving >> 98/ME behind doesn't sound overly disturbing to me) >> o the FTDI chips are not HID, so the HID backend is dead for our purposes > > The HID backend is for other device. There are many HID based device. > Typically we use native HID API to access HID device. But many programs > use libusb to access HID device under Linux. > >> o the WinUSB backend brings a WHQL signed driver, which is good, because it >> runs on all windows versions that required signed drivers (Vista 64-bit, >> Windows 7)
Just one more clarification. libusb-win32 can be made to support Vista 64bit and Windows 7 as well with a digital signature. It already works under XP 64bit. Vendors can also use libusb-win32 as their default device and get it WHQLed with their particular VID/PID if they want to do that. In that case, it will actually take precedence than the non-WHQLed FTDI driver+Vendor VID/PID combination. The FTDI WHQLed driver is for unmodified VID/PID. >> o The WinUSB How-To says that you need to get the whole driver package >> including the .inf file signed. Some postings to newsgroups suggest that >> this is not necessary. It might be that you get a warning, which shouldn't >> be that much of a problem. > > It is ok to load the driver even though there is a warning. You can do > the same with libusb-win32 device driver if somebody can pay the > digital signature (not so expensive). One company already got their > libusb-win32 based device driver certified by WHQL but they > renamed all the driver name to their own name. > >> o libusb-win32's development seems sporadic if not stalled > > You can say it is stalled right now since the SVN is 22 months old. > >> Conclusions >> >> + libusb-win32 would be good, because it works on all present windows >> platforms, and because it's supposed to work on upcoming versions, too >> >> + libusb-win32 would be good, because it allows us to use libftdi, which >> implements all the FTDI-chip specific USB communication. Using the >> information available in libftdi wouldn't be much of a problem, but it's >> certainly a lot of coding work that is mostly unrelated to OpenOCD >> >> - I have no idea about how stable and reliable libusb-win32 is > > Based on my experiences it is quite good. The filter driver can cause > many problems (including serious BSOD and lost of all USB device) > and is no longer recommended by the author. The device driver has > never caused problem for me. > >> o (Re-)writing libftdi with plain WinUSB should be possible and would remove >> the uncertainties of libusb-win32, but would burden the OpenOCD project with >> the task of keeping it stable and up to date. It would also leave out >> Windows 2000 and before. >> > > You can always use libusb-win32+libftdi for Windows 2k. > > If possible, some people with Windows knowledge can look > at the libusb-win32 1.0 branch to judge how mature (or im-mature) > it is. > > WinUSB is a good solution with or without libusb-win32. If libusb-win32's > WinUSB backend can be made to work, it is of course better since it > will benefit other open source projects as well. But a WinUSB based > solution specific to OpenOCD (for FTDI) device may be easier. > -- Xiaofan http://mcuee.blogspot.com _______________________________________________ Openocd-development mailing list Openocd-development@lists.berlios.de https://lists.berlios.de/mailman/listinfo/openocd-development
