drm_open(9)

💖 drm_open — like, the open method for a DRM file, bestie 💖

okay so real quick, this lil page lives in the Kernel API Manual and honestly? it's a short one but it matters ✨

🌸 SYNOPSIS 🌸

int drm_open (struct inode *inode , struct file *filp );

🎀 ARGUMENTS 🎀

• inode — the device inode. yep, that's the whole vibe of it 🦋
• filp — the file pointer. that's it. that's the argument 💅

✨ DESCRIPTION ✨

okay so listen 👑 — this function is mandatory for drivers, like you must use it as your file_operations.open method. no skipping, no substitutes, fr fr.

what it does: it looks up the correct DRM device and then instantiates all the per-file resources for it. all of them. the whole little starter pack for that file 🎀

oh and also? it calls the drm_driver.open driver callback. so yeah, it's out here doing the most 😭

💀 RETURN 💀

• 0 on success 🫶
• a negative errno value on failure 🙈 (that's the slay way of saying "it broke, check the errno")

🔥 SEE ALSO 🔥

all the besties in the same friend group, no cap:

• Kernel file ./drivers/gpu/drm/drm_file.c file operations(9)
• drm_file_alloc(9)
• drm_file_free(9)
• drm_release(9)
• drm_release_noglobal(9)
• drm_read(9)
• drm_poll(9)
• drm_event_reserve_init_locked(9)
• drm_event_reserve_init(9)
• drm_event_cancel_free(9)
• drm_send_event_timestamp_locked(9)
• drm_send_event_locked(9)
• drm_send_event(9)
• drm_print_memory_stats(9)
• drm_show_memory_stats(9)
• drm_show_fdinfo(9)
• drm_file_err(9)
• mock_drm_getfile(9)

and that's the whole page, bestie!! 🧚💜 this iconic little number ships from ./drivers/gpu/drm, dated October 2026 — go forth and open your DRM files responsibly 🌈⭐🍓