drm_dp_dual...x_tmds_clock(9)

💅 drm_dp_dual_mode_max_tmds_clock — a Kernel API Manual moment 🎀

okay bestie, so this is a page straight out of the Kernel API Manual, and it's about one (1) very specific little function that asks a DisplayPort dual-mode adaptor "hey girl, how fast can you go?" ✨

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🌸 NAME 🌸

drm_dp_dual_mode_max_tmds_clock — literally just: the max TMDS clock for a DP dual mode adaptor 💖

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🦋 SYNOPSIS 🦋

int drm_dp_dual_mode_max_tmds_clock (const struct drm_device *dev , enum
drm_dp_dual_mode_type type , struct i2c_adapter *adapter );

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✨ ARGUMENTS ✨

• dev — the drm_device you're rolling with 🫶
• type — which flavour of DP dual mode adaptor we're dealing with 👑
• adapter — the I2C adapter for the DDC bus, that's the road we talk down 🛣️

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💜 DESCRIPTION 💜

So the whole vibe here is: figure out the max TMDS clock the adaptor can handle. And how do we figure it out? It depends on the type of the dual mode adaptor, plus the DP_DUAL_MODE_MAX_TMDS_CLOCK register — but only on type2 adaptors, bestie. 👀

Now here's the plot twist 😭 — some type 1 adaptors have problems with registers (go read the comments in drm_dp_dual_mode_detect, they spill the tea). So on those we do not read the register at all. Instead we just simply assume a 165 MHz limit, based on the specification. No cap, that's the move. 💅

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🌈 RETURN 🌈

The maximum supported TMDS clock rate for the DP dual mode adaptor, in kHz. That's it, that's the answer 🎀

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⭐ SEE ALSO ⭐

• Kernel file ./drivers/gpu/drm/display/drm_dp_dual_mode_helper.c
• dp dual mode helpers(9)
• drm_dp_dual_mode_read(9)
• drm_dp_dual_mode_write(9)
• drm_dp_dual_mode_detect(9)
• drm_dp_dual_mode_get_tmds_output(9)
• drm_dp_dual_mode_set_tmds_output(9)
• drm_dp_get_dual_mode_type_name(9)
• drm_lspcon_get_mode(9)
• drm_lspcon_set_mode(9)

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and that's the whole page, bestie 🫶 this cutie lives in ./drivers/gpu/drm/display, and it was dated October 2026 — so yeah, mark your calendar, the kernel said what it said 💀✨