From: Benjamin Gaignard <benjamin.gaignard@st.com> To: <rjw@rjwysocki.net>, <viresh.kumar@linaro.org>, <hugues.fruchet@st.com>, <mchehab@kernel.org>, <mcoquelin.stm32@gmail.com>, <alexandre.torgue@st.com>, <pavel@ucw.cz>, <len.brown@intel.com>, <valentin.schneider@arm.com>, <vincent.guittot@linaro.org> Cc: <linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <linux-media@vger.kernel.org>, <linux-stm32@st-md-mailman.stormreply.com>, <linux-arm-kernel@lists.infradead.org>, Benjamin Gaignard <benjamin.gaignard@st.com> Subject: [RFC 3/3] media: stm32-dcmi: Inform cpufreq governors about cpu load needs Date: Tue, 26 May 2020 17:16:19 +0200 [thread overview] Message-ID: <20200526151619.8779-4-benjamin.gaignard@st.com> (raw) In-Reply-To: <20200526151619.8779-1-benjamin.gaignard@st.com> When start streaming the CPU load could remain very low because almost all the capture pipeline is done in hardware (i.e. without using the CPU) and let believe to cpufreq governor that it could use lower frequencies. If the governor decides to use a too low frequency that becomes a problem when we need to acknowledge the interrupt during the blanking time. To avoid this problem, DCMI driver informs the cpufreq governors by adding a cpufreq minimum load QoS resquest. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com> --- drivers/media/platform/stm32/stm32-dcmi.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c index b8931490b83b..774f2506b2f1 100644 --- a/drivers/media/platform/stm32/stm32-dcmi.c +++ b/drivers/media/platform/stm32/stm32-dcmi.c @@ -24,6 +24,7 @@ #include <linux/of_graph.h> #include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> +#include <linux/pm_qos.h> #include <linux/pm_runtime.h> #include <linux/reset.h> #include <linux/videodev2.h> @@ -173,6 +174,8 @@ struct stm32_dcmi { struct media_device mdev; struct media_pad vid_cap_pad; struct media_pipeline pipeline; + + struct pm_qos_request qos_request; }; static inline struct stm32_dcmi *notifier_to_dcmi(struct v4l2_async_notifier *n) @@ -827,6 +830,9 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count) else reg_set(dcmi->regs, DCMI_IER, IT_OVR | IT_ERR); + cpufreq_minload_qos_add_request(&dcmi->qos_request, + CPUFREQ_GOV_QOS_MIN_LOAD_MAX_VALUE); + return 0; err_pipeline_stop: @@ -859,6 +865,8 @@ static void dcmi_stop_streaming(struct vb2_queue *vq) struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq); struct dcmi_buf *buf, *node; + cpufreq_minload_qos_remove_request(&dcmi->qos_request); + dcmi_pipeline_stop(dcmi); media_pipeline_stop(&dcmi->vdev->entity); -- 2.15.0
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Gaignard <benjamin.gaignard@st.com> To: <rjw@rjwysocki.net>, <viresh.kumar@linaro.org>, <hugues.fruchet@st.com>, <mchehab@kernel.org>, <mcoquelin.stm32@gmail.com>, <alexandre.torgue@st.com>, <pavel@ucw.cz>, <len.brown@intel.com>, <valentin.schneider@arm.com>, <vincent.guittot@linaro.org> Cc: Benjamin Gaignard <benjamin.gaignard@st.com>, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Subject: [RFC 3/3] media: stm32-dcmi: Inform cpufreq governors about cpu load needs Date: Tue, 26 May 2020 17:16:19 +0200 [thread overview] Message-ID: <20200526151619.8779-4-benjamin.gaignard@st.com> (raw) In-Reply-To: <20200526151619.8779-1-benjamin.gaignard@st.com> When start streaming the CPU load could remain very low because almost all the capture pipeline is done in hardware (i.e. without using the CPU) and let believe to cpufreq governor that it could use lower frequencies. If the governor decides to use a too low frequency that becomes a problem when we need to acknowledge the interrupt during the blanking time. To avoid this problem, DCMI driver informs the cpufreq governors by adding a cpufreq minimum load QoS resquest. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com> --- drivers/media/platform/stm32/stm32-dcmi.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c index b8931490b83b..774f2506b2f1 100644 --- a/drivers/media/platform/stm32/stm32-dcmi.c +++ b/drivers/media/platform/stm32/stm32-dcmi.c @@ -24,6 +24,7 @@ #include <linux/of_graph.h> #include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> +#include <linux/pm_qos.h> #include <linux/pm_runtime.h> #include <linux/reset.h> #include <linux/videodev2.h> @@ -173,6 +174,8 @@ struct stm32_dcmi { struct media_device mdev; struct media_pad vid_cap_pad; struct media_pipeline pipeline; + + struct pm_qos_request qos_request; }; static inline struct stm32_dcmi *notifier_to_dcmi(struct v4l2_async_notifier *n) @@ -827,6 +830,9 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count) else reg_set(dcmi->regs, DCMI_IER, IT_OVR | IT_ERR); + cpufreq_minload_qos_add_request(&dcmi->qos_request, + CPUFREQ_GOV_QOS_MIN_LOAD_MAX_VALUE); + return 0; err_pipeline_stop: @@ -859,6 +865,8 @@ static void dcmi_stop_streaming(struct vb2_queue *vq) struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq); struct dcmi_buf *buf, *node; + cpufreq_minload_qos_remove_request(&dcmi->qos_request); + dcmi_pipeline_stop(dcmi); media_pipeline_stop(&dcmi->vdev->entity); -- 2.15.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-05-26 15:17 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-26 15:16 [RFC RESEND 0/3] Introduce cpufreq minimum load QoS Benjamin Gaignard 2020-05-26 15:16 ` Benjamin Gaignard 2020-05-26 15:16 ` [RFC 1/3] PM: QoS: " Benjamin Gaignard 2020-05-26 15:16 ` Benjamin Gaignard 2020-05-26 15:16 ` [RFC 2/3] cpufreq: governor: Use " Benjamin Gaignard 2020-05-26 15:16 ` Benjamin Gaignard 2020-05-26 15:16 ` Benjamin Gaignard [this message] 2020-05-26 15:16 ` [RFC 3/3] media: stm32-dcmi: Inform cpufreq governors about cpu load needs Benjamin Gaignard 2020-05-27 10:09 ` [RFC RESEND 0/3] Introduce cpufreq minimum load QoS Valentin Schneider 2020-05-27 10:09 ` Valentin Schneider 2020-05-27 11:17 ` Benjamin GAIGNARD 2020-05-27 11:17 ` Benjamin GAIGNARD 2020-05-27 12:14 ` Valentin Schneider 2020-05-27 12:14 ` Valentin Schneider 2020-05-27 13:11 ` Benjamin GAIGNARD 2020-05-27 13:11 ` Benjamin GAIGNARD 2020-05-27 15:02 ` Valentin Schneider 2020-05-27 15:02 ` Valentin Schneider 2020-05-27 12:22 ` Vincent Guittot 2020-05-27 12:22 ` Vincent Guittot 2020-05-27 12:48 ` Benjamin GAIGNARD 2020-05-27 12:48 ` Benjamin GAIGNARD 2020-05-27 14:54 ` Benjamin GAIGNARD 2020-05-27 14:54 ` Benjamin GAIGNARD 2020-05-27 15:03 ` Rafael J. Wysocki 2020-05-27 15:03 ` Rafael J. Wysocki -- strict thread matches above, loose matches on Subject: below -- 2020-04-24 11:40 [RFC " Benjamin Gaignard 2020-04-24 11:40 ` [RFC 3/3] media: stm32-dcmi: Inform cpufreq governors about cpu load needs Benjamin Gaignard 2020-04-24 11:40 ` Benjamin Gaignard
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