From: Biju Das biju.das.jz@bp.renesas.com
[ Upstream commit de2942828e7670526289f098df7e50b112e8ff1e ]
The interrupt controller found on RZ/G3E doesn't provide any facility to configure the wakeup sources. That's the reason why the driver lacks the irq_set_wake() callback for the interrupt chip.
But this prevent to properly enter power management states like "suspend to idle".
Enable the flags IRQCHIP_SKIP_SET_WAKE and IRQCHIP_MASK_ON_SUSPEND so the interrupt suspend logic can handle the chip correctly.
Signed-off-by: Biju Das biju.das.jz@bp.renesas.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Geert Uytterhoeven geert+renesas@glider.be Link: https://lore.kernel.org/all/20250701105923.52151-1-biju.das.jz@bp.renesas.co... Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
**Backport Status: YES**
This commit should be backported to stable kernel trees. Here's my extensive analysis:
## Summary This commit fixes a real bug where the Renesas RZ/G3E interrupt controller prevents the system from properly entering power management states like "suspend to idle" due to missing irqchip flags.
## Detailed Analysis
### 1. **Bug Fix Nature** The commit clearly fixes a functional bug as stated in the commit message: - "But this prevent to properly enter power management states like 'suspend to idle'" - The interrupt controller lacks an `irq_set_wake()` callback, which is necessary for proper suspend/resume functionality
### 2. **Small and Contained Change** The code change is minimal and well-contained: ```c .flags = IRQCHIP_SET_TYPE_MASKED, ``` changed to: ```c .flags = IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SET_TYPE_MASKED | IRQCHIP_SKIP_SET_WAKE, ```
This is a simple addition of two flags to the interrupt chip structure.
### 3. **Clear Understanding of Flags** From the kernel documentation in include/linux/irq.h: - **IRQCHIP_MASK_ON_SUSPEND**: "Mask non wake irqs in the suspend path" - This ensures interrupts that shouldn't wake the system are properly masked during suspend - **IRQCHIP_SKIP_SET_WAKE**: "Skip chip.irq_set_wake(), for this irq chip" - This tells the kernel to skip calling the non-existent irq_set_wake() callback
### 4. **Pattern Consistency** Looking at the similar Renesas driver (irq-renesas-rzg2l.c:446-448), we can see the same flags are used: ```c .flags = IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SET_TYPE_MASKED | IRQCHIP_SKIP_SET_WAKE, ``` This shows it's a well-established pattern for Renesas interrupt controllers that lack wakeup source configuration.
### 5. **No Side Effects** The change only adds flags that: - Enable proper masking of interrupts during suspend (preventing spurious interrupts) - Tell the kernel to skip calling a non-existent function - No functional changes beyond fixing the suspend issue - No API changes or new features
### 6. **Affects Users** This bug directly affects users trying to use power management features on RZ/G3E hardware. Without this fix, the system cannot properly enter suspend states, which impacts: - Power consumption - Battery life (on battery-powered devices) - System reliability during suspend/resume cycles
### 7. **Low Risk** The change has minimal risk of regression because: - It only adds standard irqchip flags that are well-tested in the kernel - The same flags are used in other similar drivers - It doesn't modify any existing logic, just adds proper flag configuration - The flags only affect suspend/resume paths, not normal operation
### 8. **Driver Maturity** While this is a relatively new driver (added in 2024), the fix addresses a clear oversight in the initial implementation. The driver is already in mainline, so systems using this hardware need this fix for proper operation.
## Conclusion This commit meets all the criteria for stable backporting: - Fixes a real bug that affects users - Minimal, well-understood change - No architectural changes or new features - Low risk of regression - Follows established patterns in similar drivers
The fix enables proper power management functionality on affected hardware, which is important for system operation and user experience.
drivers/irqchip/irq-renesas-rzv2h.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/irqchip/irq-renesas-rzv2h.c b/drivers/irqchip/irq-renesas-rzv2h.c index 0f0fd7d4dfdf..f1f7869b49cb 100644 --- a/drivers/irqchip/irq-renesas-rzv2h.c +++ b/drivers/irqchip/irq-renesas-rzv2h.c @@ -394,7 +394,9 @@ static const struct irq_chip rzv2h_icu_chip = { .irq_retrigger = irq_chip_retrigger_hierarchy, .irq_set_type = rzv2h_icu_set_type, .irq_set_affinity = irq_chip_set_affinity_parent, - .flags = IRQCHIP_SET_TYPE_MASKED, + .flags = IRQCHIP_MASK_ON_SUSPEND | + IRQCHIP_SET_TYPE_MASKED | + IRQCHIP_SKIP_SET_WAKE, };
static int rzv2h_icu_alloc(struct irq_domain *domain, unsigned int virq, unsigned int nr_irqs,