I've encountered the interrupt handle loop when using Jaguar VSC7448
chip with MAX3421, configured in level interrupt mode (default mode for
MAX3421). Upon connecting thumb drive to MAX3421, the system would
hang. After some investigation, I've traced the problem to the GPIO
interrupt controller code: by the time ocelot_irq_handler() is executed,
MAX3421 would clear its interrupt, subsequently lowering bit in GPIO
controller interrupt identify register. Because of this,
chained_irq_enter() would never be executed, and the parent interrupt
would never be cleared, resulting in a continuous interrupt handling
loop.

This could be fixed by clearing parent interrupt unconditionally, even
when no bits are set in interrupt identify registers.

Sergey Matsievskiy (1):
  pinctrl: ocelot: fix system hang on level based interrupts

 drivers/pinctrl/pinctrl-ocelot.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

-- 
2.39.5