HTPC running a full home theatre setup

[Lotus]

Okay, so I have an awesome home theatre setup right now. 5.1 surround sound system, etc. The problem I'm running into is many audio sources I want to play are simply 2 channel stereo sound, and my receiver is dated and while it supports HDMI digital input, it only supports audio profiles and sound conversion for analog inputs. This puts me in the awkward situation where if I want full 5.1 direct input I'll be using HDMI, and if I wanted 2 channel "upscaled" (not the right word) to use my full speakers I'd have to switch cables to a standard analog stereo cable and then use an audio profile to upscale it. It's too much work so I don't. Is there any way I can change driver settings or use the built-in tools with AMD's Crimson to do the upscaling on my PC side when a 2 channel audio source is detected and simply output 5.1 directly via HDMI? It would make things so much better and easier and more convenient. The GPU currently in there is an R7 260x and I'm running the latest drivers and the full crimson suite. It just sucks because one moment I'm having an awesome experience playing something like Tomb Raider (2013) with full glorious 5.1 sound, then I switch over to emulated Zelda: Wind Waker and I'm only getting sound from 2 speakers and no subwoofer. I'm really missing out.

[SSL]

I suppose it would be too much to ask the model of receiver? :rolleyes:

[Lotus]

It's an Onkyo TX-SR604. Not sure why that's relevant because I'm asking about software/drivers on the PC side.