[PATCH] wdmks: clear Header.OptionsFlags before reusing packets

[RossBencina]

Posted to mailing list 10/5/2020:

From: Stefan Hajnoczi

Capture from a Focusrite Scarlett 2i4 (1st Gen) USB audio interface with
the Windows WDM-KS hostapi times out on Windows 8.1
pa_stable_v190600_20161030 x86_64. It works when built for i686.

The Header.OptionsFlags field is zero when the packet is first given to
the device. The value is KSSTREAM_HEADER_OPTIONSF_DURATIONVALID |
KSSTREAM_HEADER_OPTIONSF_TIMEVALID when the device completes the packet.

Reusing this packet causes the event to be signalled again immediately
with DataUsed=0. The stream fails with paTimedOut once all packets have
failed in this way.

Clear the OptionsFlags field before reusing the packet. This makes the
driver happy.

Tested both x86_64 and i686 with the Focusrite Scarlett 2i4 USB driver
version 2.5.128.1.

Signed-off-by: Stefan Hajnoczi <...>
---
I am not familiar with the WDM-KS API and this patch is a result of
debugging from first principles rather than understanding the code. Why
it worked for 32-bit and failed for 64-bit remains a mystery to me.
Please review carefully.
---
 src/hostapi/wdmks/pa_win_wdmks.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/hostapi/wdmks/pa_win_wdmks.c b/src/hostapi/wdmks/pa_win_wdmks.c
index 70a48d8..f95f1ba 100644
--- a/src/hostapi/wdmks/pa_win_wdmks.c
+++ b/src/hostapi/wdmks/pa_win_wdmks.c
@@ -6536,7 +6536,11 @@ static PaError PaPinCaptureSubmitHandler_WaveCyclic(PaProcessThreadInfo* pInfo,
     pInfo->capturePackets[pInfo->captureTail & cPacketsArrayMask].packet = 0;
     assert(packet != 0);
     PA_HP_TRACE((pInfo->stream->hLog, "Capture submit: %u", eventIndex));
-    packet->Header.DataUsed = 0; /* Reset for reuse */
+
+    /* Reset header for reuse */
+    packet->Header.DataUsed = 0;
+    packet->Header.OptionsFlags = 0;
+
     ResetEvent(packet->Signal.hEvent);
     result = PinRead(pInfo->stream->capture.pPin->handle, packet);
     ++pInfo->pending;