gen7_oa_read(9)

💅 gen7_oa_read(9) — the Kernel API Manual moment 🎀

okay so bestie, this one lives in the Kernel API Manual and honestly it's giving "quiet hero of the OA pipeline" energy. Let's get into it ✨

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✨ NAME ✨

gen7_oa_read — copy status records and then the buffered OA reports, in that order, no skipping, periodt 💖

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🦋 SYNOPSIS 🦋

int gen7_oa_read (struct i915_perf_stream *stream , char __user *buf ,
size_t count , size_t *offset );

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🌸 ARGUMENTS 🌸

• stream — an i915-perf stream that was opened for OA metrics 🎀
• buf — the destination buffer, handed over by userspace
• count — how many bytes userspace is asking to read
• offset — (inout!) the current position for writing into buf. It goes in, and it comes back out changed. main character energy, truly 👑

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💜 DESCRIPTION 💜

So what this icon actually does: it checks the Gen 7 specific OA unit status registers — yep, those — and if it's necessary, it appends the matching status records for userspace (think buffer-full condition, that kind of thing 😭). Then, after that, it kicks off appending any buffered OA reports.

Order matters. Status records first, buffered reports second. That's the whole vibe check. 🔥

And it updates offset to match the number of bytes it actually managed to copy into the userspace buffer — so your bookkeeping stays honest, no cap 💅

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⭐ RETURN ⭐

zero on success, or a negative error code if it doesn't slay 😔

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🫶 SEE ALSO 🫶

Kernel file ./drivers/gpu/drm/i915/i915_perf.c (iykyk, that's the source of truth) plus this whole squad of friends:

• 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)
• i915_oa_wait_unlocked(9)
• i915_oa_poll_wait(9)
• i915_oa_read(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)

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🧚 also a lil shoutout to the source path ./drivers/gpu/drm/i915 and the date October 2026 — that's where this page comes from and when it was stamped, so you know it's fresh 💖

okay that's the whole page, go read some perf code bestie, you've got this 🌈👑