drm_dp_dpcd_writeb(9)

💅 drm_dp_dpcd_writeb(9) 💅

okay so this is a page from the Kernel API Manual, bestie — welcome to the <pink>drm_dp_dpcd_writeb</pink> glow-up ✨

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🌸 NAME 🌸

drm_dp_dpcd_writeb — write a single byte to the DPCD 🖊️💖

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✨ SYNOPSIS ✨

ssize_t drm_dp_dpcd_writeb (struct drm_dp_aux *aux , unsigned int offset
, u8 value );

like. one byte. one singular little byte. she's tiny but she's doing her job 🎀

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🦋 ARGUMENTS 🦋

• aux — the DisplayPort AUX channel, aka the vibe conduit you're sending stuff through 🔌
• offset — the address of the register to write, iykyk 📍
• value — the value to write to that register, the actual payload, the main character 💫

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👑 DESCRIPTION 👑

So here's the tea: on success this returns the number of bytes transferred, which is <rainbow>1</rainbow> — literally just the one byte, she ate and left no crumbs 🍓. On failure you get a negative error code back instead 😭 so pls check your return values, fr fr.

⚠️ big one, bestie: in most of the cases you should be using drm_dp_dpcd_write_byte instead. like, this one works, but that's the one you probably want 👀 no cap.

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🌈 SEE ALSO 🌈

goes without saying but here's the whole friend group 🫶:

• Kernel file ./include/drm/display/drm_dp_helper.h
• struct drm_dp_vsc_sdp(9)
• struct drm_dp_as_sdp(9)
• drm_dp_dsc_sink_supports_format(9)
• drm_edp_backlight_supported(9)
• drm_dp_is_uhbr_rate(9)
• struct drm_dp_aux_msg(9)
• struct drm_dp_aux_cec(9)
• struct drm_dp_aux(9)
• drm_dp_dpcd_readb(9)
• drm_dp_dpcd_read_data(9)
• drm_dp_dpcd_write_data(9)
• drm_dp_dpcd_read_byte(9)
• drm_dp_dpcd_write_byte(9)
• struct drm_dp_desc(9)
• enum drm_dp_quirk(9)
• drm_dp_has_quirk(9)
• struct drm_edp_backlight_info(9)
• struct drm_dp_phy_test_params(9)

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and that's the whole page, periodt 💅 this lil icon lives in ./include/drm/display, dated October 2026 — mwah, go write a byte, you got this 🧚💜