My 7th-level synthesist summoner is immune to all forms of energy damage.
But what happens when he gets hit by a special attack (say, a breath weapon for example) that has a secondary effect riding on top of the damage. Does he still suffer the secondary effect, or is said effect dependent on his taking damage from the attack?
Sorry, I can't think of any specific examples at the moment.
I'm guessing it would depend on the specifics. Some secondary effects would obviously rely on the primary doing damage - for instance in the case of a bleed effect. But an acid cloud that also dazes, would always daze. Unless you're immune to that too, of course.
If we look at
A creature with resistance to energy has the ability (usually extraordinary) to ignore some damage of a certain type per attack, but it does not have total immunity.
Each resistance ability is defined by what energy type it resists and how many points of damage are resisted. It doesn't matter whether the damage has a mundane or magical source.
When resistance completely negates the damage from an energy attack, the attack does not disrupt a spell. This resistance does not stack with the resistance that a spell might provide.
Some magic creatures have the supernatural ability to instantly heal damage from weapons or ignore blows altogether as though they were invulnerable.
The numerical part of a creature's damage reduction (or DR) is the amount of damage the creature ignores from normal attacks. Usually, a certain type of weapon can overcome this reduction (see Overcoming DR). This information is separated from the damage reduction number by a slash. For example, DR 5/magic means that a creature takes 5 less points of damage from all weapons that are not magic. If a dash follows the slash, then the damage reduction is effective against any attack that does not ignore damage reduction.
Whenever damage reduction completely negates the damage from an attack, it also negates most special effects that accompany the attack, such as injury poison, a monk's stunning, and injury-based disease. Damage reduction does not negate touch attacks, energy damage dealt along with an attack, or energy drains. Nor does it affect poisons or diseases delivered by inhalation, ingestion, or contact.
Attacks that deal no damage because of the target's damage reduction do not disrupt spells.
Spells, spell-like abilities, and energy attacks (even nonmagical fire) ignore damage reduction.
Sometimes damage reduction represents instant healing. Sometimes it represents the creature's tough hide or body. In either case, other characters can see that conventional attacks won't work.
If a creature has damage reduction from more than one source, the two forms of damage reduction do not stack. Instead, the creature gets the benefit of the best damage reduction in a given situation.
If we look at both of these rules and believe there is a similarity between Damage Reduction and Energy Reisstance (same thing but for different types of damage), then there could be a logical conclusion that some at least some riders would be negated. But as VRMH stated, it probably depends on what the rider is and whether the condition is inflicted by the damage or a secondary feature. If a sonic spell would cause both damage and deafness it is probably acceptable to negate the deafness if you take no sonic damage at all. You could also ask yourself, what would happen if I had Improved Evasion and saved successfully? Would I still take any of the effects then?
Sorry I don't have a more complete answer than that.