drm_crtc_helper_set_mode(9)

✨ drm_crtc_helper_set_mode(9) ✨

okay so bestie, welcome to the kernel API manual 💖 today's main character is drm_crtc_helper_set_mode, and she is lowkey the internal helper that sets a mode. like, that's literally her whole job description in NAME, no cap.

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🌸 SYNOPSIS 🌸

bool drm_crtc_helper_set_mode (struct drm_crtc *crtc , struct
drm_display_mode *mode , int x , int y , struct drm_framebuffer *old_fb
);

she returns a bool, babes. remember that, it comes back at RETURN 👀

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🎀 ARGUMENTS 🎀

• crtc — the CRTC we're programming 💅 that's the thing getting told what to do.
• mode — the mode to use. the vibe we're setting. slay.
• x — horizontal offset into the surface. horizontal, bestie. side to side.
• y — vertical offset into the surface. up and down, you got it 🦋
• old_fb — the old framebuffer, and it's here for cleanup. so like, she's the ex we're politely packing up 🙈

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💜 DESCRIPTION 💜

so the whole point: try to set mode on crtc. fr fr, that's it. but it's giving thoughtful, because she gives crtc and its associated connectors a chance to fixup or reject the mode prior to trying to set it 🔥 vibe check first, then mode set. iconic behaviour honestly.

she's an internal helper — so not your everyday public API, she's backstage crew 🧚 drivers could e.g. use her to update properties that require the entire output pipe to be disabled and re-enabled in a new configuration. the way that whole pipe has to fully go down and come back up 😭

what kind of properties? bestie I got you:

• changing whether audio is enabled on a hdmi link 🍓
• changing panel fitter attributes
• changing dither attributes

and she's not a solo act either — she's also called by the drm_crtc_helper_set_config helper function to drive the mode setting sequence. so she's out here doing collabs 👑

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⭐ RETURN ⭐

True if the mode was set successfully, false otherwise. that's the whole tea. true = slay, false = not slay 💀

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/gpu/drm/drm_crtc_helper.c overview(9)
• drm_helper_encoder_in_use(9)
• drm_helper_crtc_in_use(9)
• drm_helper_disable_unused_functions(9)
• drm_crtc_helper_atomic_check(9)
• drm_crtc_helper_set_config(9)
• drm_helper_connector_dpms(9)
• drm_helper_resume_force_mode(9)
• drm_helper_force_disable_all(9)

literally the whole friend group, go read them all 🫶

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heads up bestie: she's an internal helper, so she's not out here for everyone to just call — she's the one the config path leans on 💅

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that's the page!! 🎀 it lives in ./drivers/gpu/drm, dated October 2026, and it's part of the Kernel API Manual — mwah, go set some modes, ily 💖✨