[wdmaudiodev] Re: question on DMUS UART

  • From: Matt Gonzalez <matt@xxxxxxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Tue, 17 Feb 2004 12:02:19 -0800

For what it's worth, our PCI cards use a DMUS miniport for MIDI I/O. It works fine on dual processor 2000 & XP.

I remember that there was a minor bug in the DDK sample with handling PutMessage, but that was for MIDI output. That was a few years ago; I don't remember the specifics. It's in the mailing list archive somewhere.

Reading through my code, I did notice that I don't hold my spinlock during the call to PutMessage. That might make a difference.

For what it's worth, here's the code. This is just a modified DDK sample, so I don't think I'm giving away any trade secrets.

STDMETHODIMP_(NTSTATUS)
CMiniportDMusStreamEcho::SourceEvtsToPort()
{
   NTSTATUS        ntStatus;
   ECHOSTATUS      Status;
   DWORD           dwMidiByte;
   LONGLONG        llNewTimestamp,llLastTimestamp;

ASSERT(KeGetCurrentIrql() == DISPATCH_LEVEL);
//DOUT(DBG_PRINT, ("SourceEvtsToPort"));
if (m_fCapture) // is capture running?
{
PDMUS_KERNEL_EVENT aDMKEvt,eventTail,eventHead;
aDMKEvt = NULL;
eventTail = NULL;
eventHead = NULL;
ntStatus = STATUS_SUCCESS;
llLastTimestamp = 0;
KeAcquireSpinLockAtDpcLevel(m_pMiniport->m_pSpinLock);

do
{
//
// Get the next MIDI byte
//
Status = m_pMiniport->m_pEG->ReadMidiByte(dwMidiByte,llNewTimestamp);
if (ECHOSTATUS_OK == Status)
{
//
// Get another event from the allocator if necessary
//
if ( (NULL == eventHead) ||
(MAX_BYTES_PER_EVENT == aDMKEvt->cbEvent) ||
(llNewTimestamp != llLastTimestamp) )
{
//
// Get the new event & put it at the end of
// the linked list of capture events
//
(void) m_AllocatorMXF->GetMessage(&aDMKEvt);
if (!aDMKEvt)
{
DOUT(DBG_ERROR, ("SourceEvtsToPort can't allocate DMKEvt"));
ntStatus = STATUS_INSUFFICIENT_RESOURCES;
break;
}

// put this event at the end of the list
aDMKEvt->pNextEvt = NULL;
if (!eventHead)
{
eventHead = aDMKEvt;
}
else
{
eventTail = eventHead;
while (eventTail->pNextEvt)
{
eventTail = eventTail->pNextEvt;
}
eventTail->pNextEvt = aDMKEvt;
}
aDMKEvt->cbEvent = 0;
aDMKEvt->usChannelGroup = 1;
aDMKEvt->usFlags = DMUS_KEF_EVENT_INCOMPLETE;
aDMKEvt->ullPresTime100ns = llNewTimestamp;
llLastTimestamp = llNewTimestamp;
}
//
// Put the MIDI byte into the current event
//
if (aDMKEvt)
{
aDMKEvt->uData.abData[aDMKEvt->cbEvent] = (BYTE) dwMidiByte;
aDMKEvt->cbEvent++;
}
}
} while (ECHOSTATUS_OK == Status);

KeReleaseSpinLockFromDpcLevel(m_pMiniport->m_pSpinLock); 

       //
       // Dump the event queue back to the allocator
       //
       if (NULL != eventHead)
       {
           (void)m_sinkMXF->PutMessage(eventHead);
       }

   }
   else    //  render stream
   {
       DOUT(DBG_ERROR,("SourceEvtsToPort called on render stream"));
       ntStatus = STATUS_INVALID_DEVICE_REQUEST;
   }
   return ntStatus;
}

Hope that helps-

Matt

From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Philip Lukidis
Sent: Friday, November 28, 2003 7:22 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: question on DMUS UART


OK...I patched portcls's call to KeInitializeDpc with my driver's
routine, which called KeInitializeDpc with the passed parameters, and
then called KeSetTargetProcessorDpc, making sure to pass a mask of 0.
So far it works fine (previously it would crash right away or in less
than 1 minute or so).

This would seem to point to some synchronization problem on the part of
the DMUS port.  So again I ask did anyone get DMUSUART to work on
multiple CPUs?  Thanks.

Philip Lukidis

PS: I'll run it over the weekend here with driver verifier verifying
portcls.sys, with all options except low resources and DMA checking.




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