drm_dp_dpcd_write_byte(9)

💅 drm_dp_dpcd_write_byte — the Kernel API Manual tea ☕

okay so bestie, welcome to the drm_dp_dpcd_write_byte page from the Kernel API Manual — yes that manual, the kernel one, we're being fancy today ✨

---

🌸 NAME 🌸

drm_dp_dpcd_write_byte — it writes a single byte to the DPCD. that's it. that's the whole gig. one (1) byte. she's minimal, she's elegant, she's an icon 💅

---

🦋 SYNOPSIS 🦋

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

look at her go 😭 returns an int, takes three things, no drama. the comma spacing is literally whatever the kernel said it is and we respect it fr fr.

---

🎀 ARGUMENTS 🎀

• aux — the DisplayPort AUX channel. it's the vibe conduit, the actual pipe the byte gets sent down, the main character of this whole operation ngl 🫶
• offset — the address of the register to write. you're telling it exactly where the byte goes. location location location, periodt 📍
• value — the value to write to the register. this is the actual byte, the payload, the little guy being delivered to his destination 🍓

---

✨ DESCRIPTION ✨

so here's the whole deal: it returns zero (0) on success, or a negative error code on failure. that's the entire description. no secret extra lore, no hidden side quests, no cap 💀

lowkey obsessed with how concise she is. return value check is your bestie here — if it comes back negative, something went sideways and you should absolutely not just ignore it, ok? 🙈

---

👑 SEE ALSO 👑

the whole squad, in order, every single one of them, no skipping 🔥:

• the 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_writeb(9)
• drm_dp_dpcd_read_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)

and yes, drm_dp_dpcd_writeb(9) and drm_dp_dpcd_write_byte(9) are both in there. they're siblings. they're giving twins-but-different. don't @ me, that's just what's listed 💀

---

k bye bestie, go write that one (1) byte, you're gonna slay 💖✨🎀🦋🌸💅🫶

this lil page came from ./include/drm/display, dated October 2026, and it's the drm_dp_dpcd_write_byte(9) entry — mwah, love that for us 😘👑