Hi Stuart On 2019-02-10 23:51, Stuart Menefy wrote: > 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(). This also fixes mysterious suspend failures on Odroid XU3/XU4/HC1 :) Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > 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(-) > Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
