intel_dsb_reg_write_indexed(9)

💅 intel_dsb_reg_write_indexed — from the Kernel API Manual, section 9, bestie

Okay so picture this: you're deep in the kernel, section 9 of the Kernel API Manual, and you need to poke a register through the DSB. That's literally this function's whole job. Let's get into it 🫶

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✨ NAME ✨

intel_dsb_reg_write_indexed — emit an indexed register write to the DSB context. That's it, that's the vibe 🎀

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🌸 SYNOPSIS 🌸

void intel_dsb_reg_write_indexed (struct intel_dsb *dsb , intel_reg_t
reg , u32 val );

Returns nothing (void), takes three things, iconic behavior honestly ✨

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🦋 ARGUMENTS 🦋

• dsb — the DSB context. Your main character struct 💜
• reg — the register address. Where we're writing, bestie 📍
• val — the value. What we're writing in there 🍓

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💅 DESCRIPTION 💅

So what this function does is write a register-value pair into the command buffer of the DSB. Like, that's the whole errand. Pair goes in, buffer holds it, slay 💫

Okay but real talk — indexed writes are slower than normal MMIO writes when you're only doing a small number of writes to the same register. We're talking less than 5 or so. So if you were thinking "ooh let me index this" for like two writes to the same register… no. Not the move. Not me letting you do that 🙈

The 5-or-so cutoff is right there in the original for a reason — small batches to the same register = regular MMIO wins the race. Periodt 🔥

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/gpu/drm/i915/display/intel_dsb.c — that's the home turf of this whole situation 🧚
• DSB(9)
• intel_dsb_commit(9)
• intel_dsb_prepare(9)
• intel_dsb_cleanup(9)

Go read the whole little DSB friend group, they're all connected iykyk 👑

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⭐ cute sign-off ⭐

That's the tea, bestie — this page lives over in ./drivers/gpu/drm/i915/display, dated October 2026, and yeah the footer still says intel_dsb_reg_write_indexed(9) because some things never change 💖 Go write some indexed registers (but like, more than five times, please) 🦋