i915_oa_read(9)

💅 i915_oa_read(9) — a Kernel API Manual moment

okay bestie, welcome to i915_oa_read(9), straight out of the Kernel API Manual ✨ this one is short and sweet and honestly kind of a vibe — it's the little function that does basically one thing and does it iconically.

---

🌸 NAME 🌸

i915_oa_read — literally just calls through to &i915_oa_ops->read. that's it. that's the whole personality. no cap, it's giving "middle management" and we respect it 🫶

---

✨ SYNOPSIS ✨

int i915_oa_read (struct i915_perf_stream *stream , char __user *buf ,
size_t count , size_t *offset );

look at her go 💅 four whole arguments, all of them important, none of them optional.

---

🎀 ARGUMENTS 🎀

• stream — an i915-perf stream, opened for OA metrics. this is the main character of the whole situation 👑
• buf — the destination buffer, handed to us by userspace. their buffer, their rules (jk, our rules) 💖
• count — how many bytes userspace wants to read. the literal vibe check of the read 🌈
• offset — (inout) the current position for writing into buf. she goes in, she gets updated, she comes out changed — character development fr fr 🦋

---

💜 DESCRIPTION 💜

So what does it do? it updates offset according to the number of bytes successfully copied into the userspace buffer. that's it. that's the tea ☕ the offset bookkeeping is the entire plot, and honestly? we're obsessed with the efficiency 💀

---

🔥 RETURN 🔥

zero on success ✨ or a negative error code 😭 (ngl the negative error code is never the fun outcome, but she's part of the story too).

---

🌟 SEE ALSO 🌟

bestie, this is the friend group. every single one of them. hydrate before reading:

• the Kernel file ./drivers/gpu/drm/i915/i915_perf.c 📁
• i915 Perf Overview(9)
• i915 Perf History and Comparison with Core Perf(9)
• OA Tail Pointer Race(9)
• struct perf_open_properties(9)
• oa_buffer_check_unlocked(9)
• append_oa_status(9)
• append_oa_sample(9)
• gen8_append_oa_reports(9)
• gen8_oa_read(9)
• gen7_append_oa_reports(9)
• gen7_oa_read(9)
• i915_oa_wait_unlocked(9)
• i915_oa_poll_wait(9)
• oa_get_render_ctx_id(9)
• oa_put_render_ctx_id(9)
• i915_oa_stream_enable(9)
• i915_oa_stream_disable(9)
• i915_oa_stream_init(9)
• i915_perf_read(9)
• i915_perf_poll_locked(9)
• i915_perf_poll(9)
• i915_perf_enable_locked(9)
• i915_perf_disable_locked(9)
• i915_perf_ioctl_locked(9)
• i915_perf_ioctl(9)
• i915_perf_destroy_locked(9)
• i915_perf_release(9)
• i915_perf_open_ioctl_locked(9)
• read_properties_unlocked(9)
• i915_perf_open_ioctl(9)
• i915_perf_register(9)
• i915_perf_unregister(9)
• i915_perf_add_config_ioctl(9)
• i915_perf_remove_config_ioctl(9)
• i915_perf_init(9)
• i915_perf_fini(9)
• i915_perf_ioctl_version(9)

like, genuinely, read them all. iykyk 💫

---

okay that's the page!! mwah 💋 this little cutie lives in ./drivers/gpu/drm/i915, and she's stamped October 2026 in the Kernel API Manual — screenshot it, frame it, put it on the fridge 🧚💖 periodt.