Could I know how to avoid getting kIOUSBNotSent1Err or
kIOReturnIsoTooOld with my driver on a USB 2.0 bus?
code snippet
if (associatedPipe) {
nextSynchReadFrame = usbFrameToQueueAt;
result = associatedPipe->Read(neededDescriptor,
nextSynchReadFrame, 1, &sampleRateFrame, &completion);
}
In gdb, result returns 0, but sampleRateFrame is as follows on USB 2.0
{
frStatus = 0xe000400e,
frReqCount = 3,
frActCount = 0
}
Changing the frReqCount to 4 and the associated data structures gives
result = kIOReturnIsoTooOld
the associatedPipe has the following endpoint characteristics on USB 2.0
_endpoint = {
descriptor = 0x0,
number = 4 '\004',
direction = 1 '\001',
maxPacketSize = 4,
interval = 4 '\004'
}
On USB 1.0,
the maxPacketSize = 3, and interval = 1.
I sometimes get a kernel panic when using USB 2.0 when attempting to
perform the Read with the frReqCount set to either 3 or 4.
Any ideas?
Thanks,
David
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