drm_crtc_vbl...p_from_timer(9)

💅 drm_crtc_vbl...p_from_timer(9) — Kernel API Manual

okay so bestie, welcome to the Kernel API Manual ✨ this one is about drm_crtc_vbl...p_from_timer(9) and honestly it's a whole vibe — it's the timer-flavoured way to answer "when's the next vblank, queen?" 🕐💖

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🌸 NAME 🌸

drm_crtc_vblank_helper_get_vblank_timestamp_from_timer — the helper that implements struct &drm_crtc_funcs.get_vblank_timestamp 🎀

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✨ SYNOPSIS ✨

bool drm_crtc_vblank_helper_get_vblank_timestamp_from_timer (struct crtc *crtc, int *max_error, ktime_t *vblank_time, bool in_vblank_irq);

okay wait, the actual signature up there is literally struct drm_crtc *crtc — the manpage just wrapped it weirdly across lines. no cap, that's the real type 💀

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🫶 ARGUMENTS 🫶

• crtc — the CRTC in question 👑 like, the display pipeline star of the show
• max_error — maximum acceptable error, i.e. how sloppy we're allowed to be before it's a problem 🙈
• vblank_time — where the next vblank timestamp gets returned 💫
• in_vblank_irq — "True is called from drm_crtc_handle_vblank" — that's the literal wording from the page, and yes, it's a little cursed grammatically, but it means: this is true when you're being called from drm_crtc_handle_vblank 🧚

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🦋 DESCRIPTION 🦋

so the helper drm_crtc_helper_get_vblank_timestamp_from_timer implements get_vblank_timestamp of struct drm_crtc_funcs — but specifically for CRTCs that require a VBLANK timer 🎯 it's giving "I don't have a hardware timestamp, so I'm using the timer instead" energy, and honestly? iconic.

it returns the timestamp according to the timer's expiry time ⏰✨ periodt.

also see struct drm_crtc_funcs.get_vblank_timestamp — that's the field this whole thing is filling in, iykyk 💅

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🔥 RETURN 🔥

True on success, or false otherwise 💀 (yes that's the whole thing, no dramatic twist, bless)

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/gpu/drm/drm_vblank_helper.c
• overview(9)
• drm_crtc_vblank_atomic_flush(9)
• drm_crtc_vblank_atomic_enable(9)
• drm_crtc_vblank_atomic_disable(9)
• drm_crtc_vblank_helper_enable_vblank_timer(9)
• drm_crtc_vblank_helper_disable_vblank_timer(9)

like, go read those too bestie, the whole squad is there 🫶🌸

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and that's the page!! 💖 brought to you from ./drivers/gpu/drm, dated October 2026, under the header drm_crtc_vbl...p_from_timer(9) — slay, go timestamp something 🎀✨🦋