drm_hdcp_check_ksvs_revoked(9)

💅 drm_hdcp_check_ksvs_revoked — the kernel API manual, but make it make sense

okay so bestie, welcome to drm_hdcp_check_ksvs_revoked(9) from the Kernel API Manual ✨ this one lives in the DRM/HDCP corner of the kernel and honestly it's giving "bouncer at the club checking IDs" energy — except the IDs are HDCP receiver IDs and the club is your display pipeline 🎀

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✨ NAME ✨

drm_hdcp_check_ksvs_revoked — literally just checks the revoked status of the IDs, no cap 💅

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🦋 SYNOPSIS 🦋

int drm_hdcp_check_ksvs_revoked (struct drm_device *drm_dev , u8 *ksvs ,
u32 ksv_count );

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🌸 ARGUMENTS 🌸

• drm_dev — the drm_device you're asking the HDCP revocation check for, like "hey bestie does this thing have revoked KSVs or nah" 🫶
• ksvs — the list of KSVs (that's HDCP receiver IDs, iykyk) 👑
• ksv_count — how many KSVs you actually passed in through ksvs, so the kernel knows where the list ends 💀

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🔥 DESCRIPTION 🔥

okay so what this function does: it reads the HDCP System renewability Message — the SRM Table — from userspace, as a firmware, and then parses it to find the revoked HDCP KSVs (Receiver IDs) that DCP LLC detected 👀. Once those revoked KSVs are known, it decides the revoked state of the KSVs in the list that display drivers passed in, and the response gets sent. slay.

the SRM should be presented under the name display_hdcp_srm.bin. yes, that exact name, don't get cute with it 🎀

and the format of the SRM table that userspace needs to write into that binary file? it's defined right here:

1. the Renewability chapter on the 55th page of the HDCP 1.4 specification

https://www.digital-cp.com/sites/default/files/specifications/HDCP20Specification20Rev1_4_Secure.pdf

2. the Renewability chapter on the 63rd page of the HDCP 2.2 specification

https://www.digital-cp.com/sites/default/files/specifications/HDCP20on20HDMI20Specification20Rev2_2_Final1.pdf

go read the actual spec chapters bestie, the kernel is not gonna hold your hand on the table format 💖

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⭐ RETURN ⭐

it returns the count of the revoked KSVs, or a -ve error number if something went wrong 😭 (yes, negative error number, that's the failure path, not me being dramatic).

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🌈 SEE ALSO 🌈

• the kernel file ./drivers/gpu/drm/display/drm_hdcp_helper.c
• drm_connector_attach_content_protection_property(9)
• drm_hdcp_update_content_protection(9)

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and that's the whole page, bestie 🫶 this little icon came out of ./drivers/gpu/drm/display, dated October 2026, and the manual page itself is drm_hdcp_check_ksvs_revoked(9) — go forth and check those KSVs, periodt 💜🧚