clearing a float buffer, unclamped?

I have a float buffer which a want to set to a specific value. But when I use glClear() it seems that my values are clamped, despite that the specification says that they should not be.

I can query my clearcolor and it comes back correct. (unclamped)

I have the same behavior using DrawPixels, my values are clamped.

But when I write a fragment programs, the values are unclamped as they should.

Is there anything that i might have overlooked?

The NV_float_buffer spec clearly states: “Clears work as normal, except that values outside the range [0,1] can be written to the color buffer.”
So you can be pretty safe to assume it’s a bug in the NV30 emulation driver.