When debugging suspend problems on Exynos 5260, I had a large number of debugging prints going to the serial port after interrupts had been disabled but before the timer interrupt was shutdown. This was long enough for a timer tick to occur, but as interrupts were disabled the ISR didn't run, and so the interrupt wasn't cleared. Later when the timer was shutdown the interrupt was left asserted and so the wfi at the heart of the suspend code didn't wait, causing the suspend to fail. Currently the code which stops the timer when it is on one-shot mode and the interrupt occurs is in exynos4_mct_tick_clear(), meaning if we called this from the shutdown code exynos4_mct_tick_stop() could be called twice. So first restructure the existing code, so the check for one-shot mode and stopping the timer is moved to the ISR, leaving exynos4_mct_tick_clear() just clearing the interrupt flag. Once this has been done simply call exynos4_mct_tick_clear() from set_state_shutdown(). Stuart Menefy (2): clocksource: exynos_mct: Move one-shot check from tick clear to ISR clocksource: exynos_mct: Clear timer interrupt when shutdown drivers/clocksource/exynos_mct.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) -- 2.13.6
