Messages in this thread | | | From | David Brownell <> | Subject | Re: drivers/usb/misc/usbtest.c weirdness | Date | Mon, 12 May 2008 01:02:22 -0700 |
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On Sunday 11 May 2008, Marcin Slusarz wrote: > > test_ctrl_queue expects (?) positive and negative errnos. > what is going on here?
The sign is just a way to flag something:
/* some faults are allowed, not required */
The negative ones are required. Positive codes are optional, in the sense that, depending on how the peripheral happens to be implemented, they won't necessarily be triggered.
For example, the test to fetch a device qualifier desriptor must succeed if the device is running at high speed. So that test is marked as negative. But when it's full speed, it could legitimately fail; marked as positive. And so on for other tests.
Look at how the codes are *interpreted* to see it work.
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