STRUCT MSM_GPU_DEVFREQ(9)

💜 struct msm_gpu_devfreq(9) — the Kernel API Manual glow-up

okay so bestie, this is a page from the Kernel API Manual, section 9, and we're talking about struct msm_gpu_devfreq. It's literally the lil state-holder for all things devfreq on the msm GPU driver. Buckle up 🎀

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✨ NAME ✨

struct msm_gpu_devfreq — devfreq related state 🦋

Like, that's it. That's the whole job. It holds the devfreq-related state. Slay.

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🌸 SYNOPSIS 🌸

struct msm_gpu_devfreq {
    struct devfreq *devfreq;
    struct mutex lock;
    unsigned long idle_freq;
    struct dev_pm_qos_request boost_freq;
    u64 busy_cycles;
    ktime_t time;
    ktime_t idle_time;
    struct msm_hrtimer_work idle_work;
    struct msm_hrtimer_work boost_work;
    bool suspended;
 };

Look at her. Iconic. Every field accounted for, no notes 💅

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🫶 Members — a field-by-field vibe check 🫶

• devfreq — the devfreq instance itself. The main character, honestly.
• lock — the lock guarding "suspended", "busy_cycles", and "time". Three whole fields under one lock, that's her job fr fr 🔥
• idle_freq — a shadow frequency used while the GPU is idle. Lowkey genius: from the PoV of the devfreq governor, we're still out here sampling busyness and adjusting frequency the whole time the GPU is idle — but we use this shadow value instead, because the GPU is actually clamped to minimum frequency while it's inactive. Sneaky. Correct. Obsessed 😭
• boost_freq — a PM QoS constraint that boosts min freq for a period of time, right up until the boost expires ⭐
• busy_cycles — the last busy counter value, kept around so we can calculate elapsed busy cycles since the last sampling period 🍓
• time — time of the last sampling period. Timestamp bestie 🎀
• idle_time — time of the last transition to idle 🌈
• idle_work — used to delay clamping to idle freq on the active->idle transition. Patience is a virtue, and also a work item 💀
• boost_work — used to reset the boost_constraint after the boost period has elapsed. Cleanup crew, no cap ✨
• suspended — tracks if we're suspended 🙈

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👑 SEE ALSO 👑

Go read these next, bestie, they're all in the same friend group:

• Kernel file ./drivers/gpu/drm/msm/msm_gpu.h struct
• msm_perfcntr_group_state(9)
• struct msm_perfcntr_state(9)
• struct msm_context(9)
• msm_context_is_vmbind(9)
• msm_gpu_convert_priority(9)
• struct msm_gpu_submitqueue(9)

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💖 Sign-off 💖

That's the whole page, bestie — brought to you by ./drivers/gpu/drm/msm, version October 2026, and struct msm_gpu_devfreq(9). Go forth and sample some busyness. Periodt. 🧚‍♀️