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* Implement removal of failed transfers. The head pointer will be moved past

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the failed transfer if the transfer in question is found to be the offending
  one. Probably not quite enough and still untested.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25558 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Michael Lotz 2008-05-19 00:04:08 +00:00
parent 9cb5c9bf8f
commit a69e04b96e
1 changed files with 33 additions and 2 deletions
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35
src/add-ons/kernel/busses/usb/ohci.cpp
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@ -964,6 +964,7 @@ OHCI::_FinishTransfers()
// which causes all of the tds to become "free" (as they are
// inaccessible and not accessed anymore (as setting the head
// pointer required disabling the endpoint))
callbackStatus = B_OK;
transferDone = true;
}
@ -1031,10 +1032,14 @@ OHCI::_FinishTransfers()
transfer->transfer->Finished(callbackStatus, actualLength);
}
if (callbackStatus != B_OK) {
// remove the transfer and make the head pointer valid again
// (including clearing the halt state)
_RemoveTransferFromEndpoint(transfer);
}
// free the descriptors
_FreeDescriptorChain(transfer->first_descriptor);
// TODO: in case of cancel/error adjust the endpoint head and
// restart the endpoint by clearing the halt
delete transfer->transfer;
delete transfer;
@ -1223,6 +1228,32 @@ OHCI::_SwitchEndpointTail(ohci_endpoint_descriptor *endpoint,
void
OHCI::_RemoveTransferFromEndpoint(transfer_data *transfer)
{
// The transfer failed and the endpoint was halted. This means that the
// endpoint head pointer might point somewhere into the descriptor chain
// of this transfer. As we do not know if this transfer actually caused
// the halt on the endpoint we have to make sure this is the case. If we
// find the head to point to somewhere into the descriptor chain then
// simply advancing the head pointer to the link of the last transfer
// will bring the endpoint into a valid state again. This operation is
// safe as the endpoint is currently halted and we therefore can change
// the head pointer.
ohci_endpoint_descriptor *endpoint = transfer->endpoint;
ohci_general_td *descriptor = transfer->first_descriptor;
while (descriptor) {
if (endpoint->head_physical_descriptor == descriptor->physical_address) {
// This descriptor caused the halt. Advance the head pointer. This
// will either move the head to the next valid transfer that can
// then be restarted, or it will move the head to the tail when
// there are no more transfer descriptors. Setting the head will
// also clear the halt state as it is stored in the first bit of
// the head pointer.
endpoint->head_physical_descriptor
= transfer->last_descriptor->next_physical_descriptor;
return;
}
descriptor = (ohci_general_td *)descriptor->next_logical_descriptor;
}
}