  Global electromagnetic gyrokinetic simulations show the existence of near
threshold conditions for both a high-$n$ kinetic ballooning mode (KBM) and an
intermediate-$n$ kinetic version of peeling-ballooning mode (KPBM) in the edge
pedestal of two DIII-D H-mode discharges. When the magnetic shear is reduced in
a narrow region of steep pressure gradient, the KPBM is significantly
stabilized, while the KBM is weakly destabilized and hence becomes the
most-unstable mode. Collisions decrease the KBM's critical $\beta$ and increase
the growth rate.
