Thread (15 messages) flat view 15 messages, 3 authors, 2025-11-17
STALE283d REVIEWED: 6 (5M)

2 review trailers.

[PATCH v5 4/7] clocksource/drivers/exynos_mct: Use percpu interrupts only on ARM64

From: Will McVicker <hidden>
Date: 2025-10-23 20:53:10
Also in: linux-samsung-soc, lkml
Subsystem: clocksource, clockevent drivers, the rest · Maintainers: Daniel Lezcano, Thomas Gleixner, Linus Torvalds

From: Marek Szyprowski <m.szyprowski@samsung.com>

For some unknown reasons forcing percpu interrupts for local timers
breaks CPU hotplug for 'little' cores on legacy ARM 32bit Exynos based
machines (for example Exynos5422-based Odroid-XU3/XU4 boards). Use percpu
flag only when driver is compiled for newer ARM64 architecture.

Fixes: f3cec54ee3bf ("clocksource/drivers/exynos_mct: Set local timer interrupts as percpu")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Krzysztof Kozlowski <redacted>
---
 drivers/clocksource/exynos_mct.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index a5ef7d64b1c2..1429b9d03a58 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -597,7 +597,8 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
 			if (request_irq(mct_irq,
 					exynos4_mct_tick_isr,
 					IRQF_TIMER | IRQF_NOBALANCING |
-					IRQF_PERCPU,
+					(IS_ENABLED(CONFIG_ARM64) ?
+					 IRQF_PERCPU : 0),
 					pcpu_mevt->name, pcpu_mevt)) {
 				pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
 									cpu);
-- 
2.51.1.821.gb6fe4d2222-goog

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