linux/drivers/clocksource/timer-sun4i.c

226 lines
6.1 KiB

clocksource/drivers/timer-sun4i: Advertise a real minimum delta sun4i_clkevt_next_event() compensates for the timer stop/start synchronization delay by programming evt - TIMER_SYNC_TICKS into the hardware interval register. The clockevent device currently advertises TIMER_SYNC_TICKS as min_delta_ticks, so the clockevents core is allowed to call set_next_event() with evt == TIMER_SYNC_TICKS. That programs a zero-tick interval. With oneshot/highres/nohz timer operation this can leave the next event stuck, which was observed as a boot hang on Allwinner D1 after the clockevents core started reusing forced minimum-delta events. Advertise one extra tick instead, so the smallest event accepted by the core still programs at least one hardware tick after the synchronization compensation. Fixes: 12e1480bcb49 ("clocksource: sun4i: Report the minimum tick that we can program") Reported-by: Indrek Kruusa <indrek.kruusa@gmail.com> Closes: https://lore.kernel.org/linux-riscv/CA+fTLhgLmTY+exGujKf8OYYQvcEW5X5NJ_5sLq2AYL6zER2c0A@mail.gmail.com/ Assisted-by: Codex:gpt-5.5 Signed-off-by: Felix Yan <felixonmars@archlinux.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Tested-by: Indrek Kruusa <indrek.kruusa@gmail.com> Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-riscv/CA+fTLhgLmTY+exGujKf8OYYQvcEW5X5NJ_5sLq2AYL6zER2c0A@mail.gmail.com/ Link: https://patch.msgid.link/20260624220434.4183732-1-felixonmars@archlinux.org
2026-06-25 06:04:34 +08:00