Re: [PATCH v2 4/8] PM / devfreq: rockchip-dfi: add NO_INTERRUPT perf capability

[Choi Chanwoo <cwchoi00@gmail.com>]

On 9/22/2026 5:32 AM, Sebastian Reichel wrote:
> From: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> 
> The perf subsystem's PERF_PMU_CAP_NO_INTERRUPT is a bit of a
> misnomer.[1] Instead of meaning that the PMU has no interrupt, it
> actually means that the PMU does support sampling. On CPU PMUs, this is
> equivalent to not having an interrupt, but for uncore PMUs like the
> rockchip-dfi PMU is, no meaningful sample data could ever be generated
> regardless of whether or not there is an interrupt, as it is not a CPU.
> 
> Since rockchip-dfi doesn't seem to make use of the interrupt the DT
> provides it with anyway, this was probably never a confusion that
> existed in this case; the capability flag was likely just forgotten.
> 
> Add PERF_PMU_CAP_NO_INTERRUPT to the set flags for the pmu struct's
> capabilities member, so that the perf core knows about this limitation.
> 
> Fixes: 4d586b5724d3 ("PM / devfreq: rockchip-dfi: Add perf support")
> Link: https://lore.kernel.org/all/20250619140442.GH1613376@noisy.programming.kicks-ass.net/ [1]
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>  drivers/devfreq/event/rockchip-dfi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> index 5339616f7ca6..dd9edfd6a674 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -646,7 +646,7 @@ static int rockchip_ddr_perf_init(struct rockchip_dfi *dfi)
>  	seqlock_init(&dfi->count_seqlock);
>  
>  	pmu->module = THIS_MODULE;
> -	pmu->capabilities = PERF_PMU_CAP_NO_EXCLUDE;
> +	pmu->capabilities = PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT;
>  	pmu->task_ctx_nr = perf_invalid_context;
>  	pmu->attr_groups = attr_groups;
>  	pmu->event_init  = rockchip_ddr_perf_event_init;
> 

Acked-by: Chanwoo Choi <cw00.choi@samsung.com>

-- 
Best Regards,
Chanwoo Choi
Principal Engineer, Samsung Electronics