What happens when a party’s member uses an healing spell on an unconscious PC who has spell resistance?

The Spell Resistance (Ex) ability reads, in part:

The possessor does not have to do anything special to use spell resistance. The creature need not even be aware of the threat for its spell resistance to operate.

My PC fell unconscious in the middle of a fight, when the cleric approached me to use Cure Serious Wounds (Player’s Handbook v.3.5, p. 215) I stated that I had Spell Resistance and I didn’t lower it in order to protect myself while I was on the ground. Our DM ruled that being unconscious implies that my spell resistance isn’t active.

This was certaintly helpful, my PC would be already dead if it wasn’t for that Cure Serious Wounds, but this takes me to the point: was it all legal?

Does an harmless spell has to pass the caster level check in order to affect a creature with Spell Resistance?

Does an unconscious creature has Spell Resistance equal to zero?