Hello, everyone!
I wrote some simple virtual audio driver based on MSVAD Simple example. It
just copying data from its wave out pin (speakers) to its microphone. It
works fine, but sometimes my driver crash on my Windows (Win 7 x64 SP1
Build 7601).
Here is what I just changed (*basedma.cpp*) in an example:
In AllocateBuffer function:
STDMETHODIMP_(NTSTATUS)
CMiniportWaveCyclicStreamMSVAD::AllocateBuffer
(
IN ULONG BufferSize,
IN PPHYSICAL_ADDRESS PhysicalAddressConstraint OPTIONAL
)
{
...
*// My code*
*if *(ntStatus == STATUS_SUCCESS && m_pvSharedBuffer == NULL) {
m_pvSharedBuffer = (PVOID) ExAllocatePoolWithTag(NonPagedPool,
BufferSize, 'VOG');
*if *(!m_pvSharedBuffer) {
ntStatus = STATUS_INSUFFICIENT_RESOURCES;
} *else *{
m_ulSharedBufferSize = BufferSize;
m_pvSharedBufferCur = m_pvSharedBuffer;
}
}
*// My code*
}
In CopyFrom function (copying data from the internal buffer):
STDMETHODIMP_(void)
CMiniportWaveCyclicStreamMSVAD::CopyFrom
(
IN PVOID Destination,
IN PVOID Source,
IN ULONG ByteCount
)
{
*// My code*
*if *(m_pvSharedBuffer != NULL) {
SIZE_T szFillSize = (PUCHAR) m_pvSharedBufferCur - (PUCHAR)
m_pvSharedBuffer;
*if *(ByteCount >= szFillSize) {
RtlCopyMemory(Destination, m_pvSharedBuffer, szFillSize);
m_pvSharedBufferCur = m_pvSharedBuffer;
} *else *{
RtlCopyMemory(Destination, m_pvSharedBuffer, ByteCount);
PUCHAR pcNewBeginning = (PUCHAR) m_pvSharedBuffer + ByteCount;
SIZE_T szNewSize = szFillSize-ByteCount;
RtlMoveMemory(m_pvSharedBuffer, pcNewBeginning, szNewSize);
m_pvSharedBufferCur = (PUCHAR) m_pvSharedBuffer + szNewSize;
}
}
*// My code*
}
In CopyTo function (copying data to the internal buffer):
STDMETHODIMP_(void)
CMiniportWaveCyclicStreamMSVAD::CopyTo
(
IN PVOID Destination,
IN PVOID Source,
IN ULONG ByteCount
)
{
*// My code*
*if *(m_pvSharedBuffer != NULL) {
*if *(ByteCount > m_ulSharedBufferSize) {
* // if incoming data is larger than internal buffer*
Source = (PUCHAR) Source + (ByteCount-m_ulSharedBufferSize);
ByteCount = m_ulSharedBufferSize;
m_pvSharedBufferCur = m_pvSharedBuffer;
} *else *{
SIZE_T szFillSize = (PUCHAR) m_pvSharedBufferCur - (PUCHAR)
m_pvSharedBuffer;
SIZE_T szBytesLeft = m_ulSharedBufferSize - szFillSize;
*if *(szBytesLeft < ByteCount) {
SIZE_T szMemShift = ByteCount-szBytesLeft;
PUCHAR pcNewBeginning = (PUCHAR) m_pvSharedBuffer +
szMemShift;
szFillSize -= szMemShift;
RtlMoveMemory(m_pvSharedBuffer, pcNewBeginning, szFillSize);
m_pvSharedBufferCur = (PUCHAR) m_pvSharedBuffer +
szFillSize;
}
}
RtlCopyMemory(m_pvSharedBufferCur, Source, ByteCount);
m_pvSharedBufferCur = (PUCHAR) m_pvSharedBufferCur + ByteCount;
}
*// My code*
}
Also I removed everything related to saving data into the file (in the
*basewave.cpp*). The following code was removed:
NTSTATUS
CMiniportWaveCyclicStreamMSVAD::Init
(
IN PCMiniportWaveCyclicMSVAD Miniport_,
IN ULONG Pin_,
IN BOOLEAN Capture_,
IN PKSDATAFORMAT DataFormat_
)
{
...
* // If this is not the capture stream, create the output
file. // if (!m_fCapture) { DPF(D_TERSE,
("SaveData %p", &m_SaveData)); ntStatus =
m_SaveData.SetDataFormat(DataFormat_); if
(NT_SUCCESS(ntStatus)) { ntStatus =
m_SaveData.Initialize(); } }*...
}
STDMETHODIMP_(NTSTATUS)
CMiniportWaveCyclicStreamMSVAD::SetFormat
(
IN PKSDATAFORMAT Format
)
{
...
* if (!m_fCapture) {
ntStatus = m_SaveData.SetDataFormat(Format); }*...
}
STDMETHODIMP
CMiniportWaveCyclicStreamMSVAD::SetState
(
IN KSSTATE NewState
)
{
...
* // Wait until all work items are completed.
// if (!m_fCapture) {
m_SaveData.WaitAllWorkItems(); }*...
}
So what I am doing wrong?
