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QTHID crashes under OSX lion when Funcube Dongle is Connected to the USB port #7

st0ne opened this Issue · 7 comments

2 participants



when the funcube dongle is connected to the usb port. then the qthid will close immediatly. i've tried with qt creator, to see where the problem is.

it says:
Could not access Memory

The error will be at line 468 of hidmac.c

i don't know where the problem is, my programing skill is not too good ;-)

here is the code:

/* Attach the new report object to the end of the list. /
if (dev->input_reports == NULL) {
The list is empty. Put it at the root. /
dev->input_reports = rpt;
else {
Find the end of the list and attach. */
struct input_report *cur = dev->input_reports;
while (cur->next != NULL)
cur = cur->next;
cur->next = rpt;


Which version of OS X?


oh sorry, i forgot... it's osx lion GM.


Ok, thanks. I will look at it when I get lion.


ok thanks, if you have some ideas now, i can test it ;-)


Sorry, I really have no idea whatsoever since I have never worked inside the hidapi files - they come from a different project written by somebody else.


Analysis provided by Matt on the FCDevelopment group:

OK, so I've been playing with a small test harness that uses fcd.c and hidmac.c to do try various things.

Once I start making more than a couple of calls to various fcd functions I get segmentation faults.
I have tried compiling as both 32 bit and 64 bit and both have issues.

I began to think that the problem might be something to do with continually opening and closing the FCD,
using fcdOpen and fcdClose, so I modified fed.c so that fcdOpen reuses a previously opened connection and
fcdClose is a no-op.

My test harness now seems to run without issues every time.

I am no expert with IOKit but what I think is happening is that fcd.c opens the HID device in IOKit, quickly does
its thing and then closes the HID device. Sometime after this IOKit is coming along with a callback to hidmac.c
but the device has already been closed and this generates the segfault.

This feels to me like a bug in IOKit but as I say I'm no expert. It might be a bug in hidapi, I don't think it is a bug in
Qthid but it might be possible to mitigate the problem in Qthid by reusing the hid device rather than opening/closing
it for every query to the device.

@csete csete referenced this issue from a commit
Mike K0ZAP Fix hidmac on Lion. Issue #7. 192c512
@csete csete closed this
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