acpi_evaluate_ost(9)

💅 acpi_evaluate_ost(9) — like, the Kernel API Manual entry, bestie ✨

okay so this is acpi_evaluate_ost, and it lives in section 9 of the kernel API manual (yes, the man-page-y one). it's short, it's sweet, and if you're writing an ACPI hotplug handler you literally cannot skip it. no cap. 🫶

🌸 NAME 🌸

acpi_evaluate_ost — evaluates _OST for hotplug operations 💖

✨ SYNOPSIS ✨

acpi_status acpi_evaluate_ost (acpi_handle handle , u32 source_event ,
u32 status_code , struct acpi_buffer *status_buf );

🎀 ARGUMENTS 🎀

• handle — the ACPI device handle. the whole "who are we talking about" of it all 👑
• source_event — the source event code 🦋
• status_code — the status code 🌸
• status_buf — optional detailed information, and it's NULL if there's none. so like, optional-optional 🙈

💜 DESCRIPTION 💜

so the entire job here is: evaluate _OST for hotplug operations. that's it. that's the vibe check. ✨

real talk though: every single ACPI hotplug handler must call this function when it's evaluating _OST for hotplug operations. not "should", not "if you feel like it" — must. periodt. 💅

and the genuinely iconic part? when the platform doesn't support _OST, this function literally has no effect. it just quietly does nothing. no error, no drama, no mess. lowkey the most well-adjusted function in the kernel 😭🫶

🌈 SEE ALSO 🌈

kernel file ./drivers/acpi/utils.c, and honestly the whole friend group:

• acpi_handle_list_equal(9)
• acpi_handle_list_replace(9)
• acpi_handle_list_free(9)
• acpi_device_dep(9)
• acpi_handle_path(9)
• acpi_handle_printk(9)
• __acpi_handle_debug(9)
• acpi_evaluation_failure_warn(9)
• acpi_has_method(9)
• acpi_evaluate_ej0(9)
• acpi_evaluate_lck(9)
• acpi_evaluate_reg(9)
• acpi_evaluate_dsm(9)
• acpi_check_dsm(9)
• acpi_dev_uid_to_integer(9)
• acpi_dev_found(9)
• acpi_dev_present(9)
• acpi_dev_get_next_match_dev(9)
• acpi_dev_get_first_match_dev(9)
• acpi_reduced_hardware(9)
• acpi_dev_is_video_device(9)
• acpi_match_platform_list(9)

mwah 💋 that's the whole page. shipped from ./drivers/acpi, dated October 2026, and yeah — it's giving reference manual, it's giving hotplug royalty. go call your _OST. 🧚⭐