usb_audio: Correct mixup between Input terminals and Input streams.

An "Input" terminal in USB audio terms refers to any stream of audio
going "in" to the USB device, whether that be from the outside world
(e.g. a line in jack) or from the computer (e.g. via USB OUT endpoints.)

So we cannot rely on the terminal type to tell us whether it is an in
or an out for our purposes, we have to check the stream type, and then
use that to declare to multi_audio what kind of stream we have.

Fixes USB audio mixing up inputs and outputs, especially on devices
that only have one or the other and not both. (QEMU manifested
this problem.)

src/add-ons/kernel/drivers/audio/usb/AudioControlInterface.cpp

@@ -1066,15 +1066,12 @@ AudioControlInterface::InitACHeader(size_t interface,
 
 uint32
 AudioControlInterface::GetChannelsDescription(
-		Vector<multi_channel_info>& Channels, multi_description* Description,
+	Vector<multi_channel_info>& Channels, multi_description* Description,
-		Vector<_AudioControl*>&Terminals)
+	Vector<_AudioControl*>& Terminals, bool isForInput)
 {
 	uint32 addedChannels = 0;
 
 	for (int32 i = 0; i < Terminals.Count(); i++) {
-		bool bIsInputTerminal
-			= Terminals[i]->SubType() == USB_AUDIO_AC_INPUT_TERMINAL;
-
 		AudioChannelCluster* cluster = Terminals[i]->OutCluster();
 		if (cluster == NULL || cluster->ChannelsCount() <= 0) {
 			TRACE(ERR, "Terminal #%d ignored due null "
@@ -1083,9 +1080,9 @@ AudioControlInterface::GetChannelsDescription(
 		}
 
 		uint32 channels = GetTerminalChannels(Channels, cluster,
-			bIsInputTerminal ? B_MULTI_INPUT_CHANNEL : B_MULTI_OUTPUT_CHANNEL);
+			isForInput ? B_MULTI_INPUT_CHANNEL : B_MULTI_OUTPUT_CHANNEL);
 
-		if (bIsInputTerminal)
+		if (isForInput)
 			Description->input_channel_count += channels;
 		else
 			Description->output_channel_count += channels;
@@ -1134,7 +1131,7 @@ AudioControlInterface::GetTerminalChannels(Vector<multi_channel_info>& Channels,
 
 uint32
 AudioControlInterface::GetBusChannelsDescription(
-		Vector<multi_channel_info>& Channels, multi_description* Description)
+	Vector<multi_channel_info>& Channels, multi_description* Description)
 {
 	uint32 addedChannels = 0;
 

src/add-ons/kernel/drivers/audio/usb/AudioControlInterface.h

@@ -283,7 +283,8 @@ public:
 			uint32			GetChannelsDescription(
 								Vector<multi_channel_info>& Channels,
 								multi_description* Description,
-								Vector<_AudioControl*>& USBTerminals);
+								Vector<_AudioControl*>& USBTerminals,
+								bool isForInput);
 			uint32			GetBusChannelsDescription(
 								Vector<multi_channel_info>& Channels,
 								multi_description* Description);

src/add-ons/kernel/drivers/audio/usb/Device.cpp

@@ -493,17 +493,18 @@ Device::_MultiGetDescription(multi_description* multiDescription)
 
 	Description.control_panel[0] = '\0';
 
-	Vector<_AudioControl*> USBTerminals;
+	Vector<multi_channel_info> Channels;
 
-	// channels (USB I/O terminals) are already in fStreams
+	// channels (USB I/O terminals) are already in fStreams in outputs->inputs order.
-	// in outputs->inputs order, use them.
 	for (int i = 0; i < fStreams.Count(); i++) {
-		USBTerminals.PushBack(fAudioControl.Find(fStreams[i]->TerminalLink()));
+		Vector<_AudioControl*> USBTerminal;
+		USBTerminal.PushBack(fAudioControl.Find(fStreams[i]->TerminalLink()));
+
+		fAudioControl.GetChannelsDescription(Channels, &Description, USBTerminal,
+			fStreams[i]->IsInput());
 		fStreams[i]->GetFormatsAndRates(&Description);
 	}
 
-	Vector<multi_channel_info> Channels;
-	fAudioControl.GetChannelsDescription(Channels, &Description, USBTerminals);
 	fAudioControl.GetBusChannelsDescription(Channels, &Description);
 
 	// Description.request_channel_count = channels + bus_channels;