vga_switcheroo_unlock_ddc(9)

💅 vga_switcheroo_unlock_ddc — the kernel API manual, bestie edition ✨

Okay so this one lives in the Kernel API Manual, and honestly? It's giving "short function, big feelings." Let's get into it 🫶

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✨ NAME ✨

vga_switcheroo_unlock_ddc — switch DDC lines back to previous owner

Literally what it says on the tin, no cap 💖

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🎀 SYNOPSIS 🎀

int vga_switcheroo_unlock_ddc (struct pci_dev *pdev );

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🌸 ARGUMENTS 🌸

• pdev — client pci device. That's your main character right there 👑

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🦋 DESCRIPTION 🦋

So here's the tea 🍓: after you call vga_switcheroo_lock_ddc, this is the function that switches the DDC lines back to the previous owner. It's the undo button, the "ok we're done here" text, the putting-your-chair-back moment 💅

And listen — you must call this even if vga_switcheroo_lock_ddc returned an error. Yeah, even then. Not optional, fr fr. It's the polite thing to do and also the required thing to do 😌

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🔥 RETURN 🔥

On success, you get back the previous DDC owner — i.e. the client identifier of pdev 🎉 Otherwise you get a negative int, and here's the breakdown:

• -ENODEV — if no handler has registered, or if the handler does not support switching the DDC lines 🙈
• a negative value returned by the handler — that gets propagated straight back to you, the caller. No filter, no edits, we pass it along 💀
• -EINVAL — this is what happens if you invoke this function without calling vga_switcheroo_lock_ddc first. That's not allowed, bestie. Order matters 🚨

Lowkey a big deal: skipping the lock first is not allowed and will result in -EINVAL. Do not pass go, do not collect your DDC lines 🎀

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👑 SEE ALSO 👑

The whole friend group, assembled 🌈

• Kernel file ./drivers/gpu/vga/vga_switcheroo.c Overview(9)
• struct vga_switcheroo_client(9)
• struct vgasr_priv(9)
• vga_switcheroo_register_handler(9)
• vga_switcheroo_unregister_handler(9)
• vga_switcheroo_handler_flags(9)
• vga_switcheroo_register_client(9)
• vga_switcheroo_register_audio_client(9)
• vga_switcheroo_client_probe_defer(9)
• vga_switcheroo_get_client_state(9)
• vga_switcheroo_unregister_client(9)
• vga_switcheroo_client_fb_set(9)
• vga_switcheroo_lock_ddc(9)
• Manual switching and manual power control(9)
• vga_switcheroo_process_delayed_switch(9)
• Driver power control(9)
• vga_switcheroo_init_domain_pm_ops(9)

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And that's the whole page!! 🧚 From ./drivers/gpu/vga, dated October 2026, in the Kernel API Manual — mwah, slay, periodt 💜🦋✨