gen8_oa_read(9)

💅 gen8_oa_read(9) — the kernel API manual, but make it make sense

okay so bestie, welcome to the <cyan>Kernel API Manual</cyan> entry for gen8_oa_read ✨ no cap, this one's genuinely cute once you get the vibe.

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🌸 NAME 🌸

gen8_oa_read — copy status records then buffered OA reports 💖

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✨ SYNOPSIS ✨

int gen8_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, and it's gotta be one that was opened for OA metrics 👑
• buf — the destination buffer that userspace handed over 🫶
• count — how many bytes userspace actually wants to read, literally the byte count
• offset — (inout) the current position for writing into buf, so it goes in and comes back out updated 🦋

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💜 DESCRIPTION 💜

So what this icon does: it checks the OA unit status registers, and if it needs to, it appends the corresponding status records for userspace — think a buffer-full condition, that kind of thing — and then it kicks off appending any buffered OA reports. it's giving "cleanup then deliver" main character energy 💅

It updates offset according to the number of bytes successfully copied into the userspace buffer. tracking the receipts, fr fr ✨

NB: some data may be successfully copied to the userspace buffer even if an error is returned, and that's reflected in the updated offset. so yeah — error doesn't always mean nothing happened, bestie 😭 keep an eye on that offset 🙈

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🔥 RETURN 🔥

zero on success, or a negative error code 🍓

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🌈 SEE ALSO 🌈

Kernel file ./drivers/gpu/drm/i915/i915_perf.c plus the whole friend group:

• 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)
• gen7_append_oa_reports(9)
• gen7_oa_read(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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that's the whole page, bestie, you ate that 🫶 this one lives in <purple>./drivers/gpu/drm/i915</purple> and it's dated <mint>October 2026</mint>, and yes the footer still says gen8_oa_read(9) because we stay on brand 💖✨🎀