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Date:   Thu, 15 Jun 2023 15:13:16 +0200
From:   Sascha Hauer <s.hauer@pengutronix.de>
To:     linux-rockchip@lists.infradead.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, Heiko Stuebner <heiko@sntech.de>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>, kernel@pengutronix.de,
        Michael Riesch <michael.riesch@wolfvision.net>,
        Robin Murphy <robin.murphy@arm.com>,
        Vincent Legoll <vincent.legoll@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>, devicetree@vger.kernel.org,
        Sebastian Reichel <sebastian.reichel@collabora.com>
Subject: Re: [PATCH v5 16/25] PM / devfreq: rockchip-dfi: Add perf support
Message-ID: <20230615131316.GF15436@pengutronix.de>
References: <20230524083153.2046084-1-s.hauer@pengutronix.de>
 <20230524083153.2046084-17-s.hauer@pengutronix.de>
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On Wed, May 24, 2023 at 10:31:44AM +0200, Sascha Hauer wrote:
> +static int rockchip_ddr_perf_event_add(struct perf_event *event, int flags)
> +{
> +	struct rockchip_dfi *dfi = container_of(event->pmu, struct rockchip_dfi, pmu);
> +
> +	dfi->active_events++;
> +
> +	if (dfi->active_events == 1)

We need to initialize dfi->last_perf_count here:

		rockchip_dfi_read_counters(dfi, &dfi->last_perf_count);

dfi->last_perf_count contains the start values for the counters and
without initializing this the u32 counter overflows are not correctly
handled.

Sascha


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