On Wed, Jun 23, 2021 at 8:13 PM Xiaofan Chen <xiaof...@gmail.com> wrote: > > On Sat, Jun 19, 2021 at 5:11 PM Xiaofan Chen <xiaof...@gmail.com> wrote: > > > > On Sun, Jun 13, 2021 at 7:02 PM Xiaofan Chen <xiaof...@gmail.com> wrote: > > > > > > I can see that there is an issue with ST-Link now. I can > > > > reproduce it myself. > > > > https://sourceforge.net/p/openocd/tickets/308/ > > > > https://github.com/libusb/libusb/issues/928 > > > > > > Based on my investigation, the issue is not with libusb > > > but rather openocd. Please take a look at the libusb > > > ticket #928 to see if my analysis is correct or not. Thanks. > > > > > > > Just wondering if anyone has looked into Ticket 308. Thanks. > > https://sourceforge.net/p/openocd/tickets/308/ > > > > I do not have issues connecting to stlink with the latest > > libusb git from the following project which also uses libusb. > > https://github.com/stlink-org/stlink > > I have made some progress to identify the particular libusb > commit which causes the differences in behavior. > > Please refer to my updates here. > https://sourceforge.net/p/openocd/tickets/308/ > https://github.com/libusb/libusb/issues/928 > > Particular complicated libusb commit (by right it should be splitted > into multiple changes, but anyway we are short of maintainers): > https://github.com/libusb/libusb/commit/32a22069428cda9d63aa666e92fb8882a83d4515 > > However, I am not so sure if that paticular change is the root cause > or openocd stlink_usb.c is the culprit.
Thanks to the pointer of the original reporter (asier70) and Antonio Borneo in openocd ticket 308, I think I have identify the issue in stlink_usb.c. Yes the above libusb patch libusb (32a2206) changed a bit of the behavior of libusb code but openocd stlink_usb.c does not handle the context right. It assumes that libusb_init() is called with NULL context but that is not true as per libusb_helper.c. Why FTDI adapter does not have such issue, because it does not use libusb_helper.h and uses libusb by itself with the mpsse backend. https://github.com/ntfreak/openocd/blob/master/src/jtag/drivers/mpsse.c Why does other libusb_helper based adapter not have such an issue, because they do not use async transfer and do not use the context. Please help to check if my analysis is correct or not. Thanks. I am not a programmer myself. -- Xiaofan
