diff options
| author | Felix Yan <felixonmars@archlinux.org> | 2026-06-25 06:04:34 +0800 |
|---|---|---|
| committer | Daniel Lezcano <daniel.lezcano@kernel.org> | 2026-08-13 18:13:01 +0200 |
| commit | d21808328225ab8cee46885bf9a0dffcefbe630e (patch) | |
| tree | ffd67af97e29d2f5ee4cd50132f8a56ca067de8c /drivers/clocksource | |
| parent | 6d6dd3863aa35f1873c7e8b82b1ee66244255a3a (diff) | |
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
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/timer-sun4i.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/clocksource/timer-sun4i.c b/drivers/clocksource/timer-sun4i.c index 7bdcc60ad43c..c2d04ab7cf2d 100644 --- a/drivers/clocksource/timer-sun4i.c +++ b/drivers/clocksource/timer-sun4i.c @@ -208,7 +208,7 @@ static int __init sun4i_timer_init(struct device_node *node) sun4i_timer_clear_interrupt(timer_of_base(&to)); clockevents_config_and_register(&to.clkevt, timer_of_rate(&to), - TIMER_SYNC_TICKS, 0xffffffff); + TIMER_SYNC_TICKS + 1, 0xffffffff); /* Enable timer0 interrupt */ val = readl(timer_of_base(&to) + TIMER_IRQ_EN_REG); |