Photon Geyser ignores the target's Ability. So does this ignore all Abilities, or are there some certain Abilities that don't get affected?
Sunsteel Strike inflicts damage, ignoring all ignorable Abilities (Abilities that could affect the success or damage of a move) during its execution. However, it does not ignore Abilities if it is called by another move rather than directly used.
Source
The same description is on the Photon Geyser page.
Hope I helped!