DirectX: BC4 texture format can crash PIX

[bahbar]

I've been tracing a program that uses a BC4 texture with PIX.

It looks like for this format, PIX (from Feb 2010 SDK) is trying to capture
2x the amount of data pointed by the subresource_data on CreateTexture, and
therefore raises an access violation error.

More data: if the BC4 texture is not big, PIX does not crash (it presumably
captures random, but allocated, memory at that point), but shows a size of
resource that is 2x what I expect (i.e. 16BPE instead of 8BPE, at least
according to
http://msdn.microsoft.com/en-us/library/bb694531%28VS.85%29.aspx#BC4 ).

The program actually shows the texture normally if PIX is not running.