xe_device_wmb(9)

💅 xe_device_wmb(9) — like, the whole kernel API manual moment, bestie

okay so real talk, this is xe_device_wmb(9) from the Kernel API Manual, and it's short but it's important, so let's get into it 🫶

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✨ NAME ✨

xe_device_wmb — the device-specific write memory barrier. that's it, that's the vibe 💫

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🌸 SYNOPSIS 🌸

void xe_device_wmb (struct xe_device *xe );

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🎀 ARGUMENTS 🎀

• xe — the xe_device. that's your girl. hand her over and she does the thing 💖

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🦋 DESCRIPTION 🦋

okay so here's the tea ☕ — wmb is sufficient for a barrier if we use system memory. like, it's literally enough. iconic behavior honestly.

BUT. and this is the big but 🔥 — on discrete platforms with device memory, that is not enough, and we additionally need to issue a register write. no cap.

and then the cute part: since it doesn't matter which register we write to, we use the read-only VF_CAP register — which is also marked as accessible by the VFs. efficiency queen 👑✨

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🧚 SEE ALSO 🧚

• Kernel file ./drivers/gpu/drm/xe/xe_device.c
• xe_file_get(9)
• xe_file_put(9)
• xe_is_xe_file(9)
• xe_device_is_admin_only(9)
• xe_device_create(9)
• xe_device_init_early(9)
• xe_device_probe_early(9)
• xe_device_is_l2_flush_optimized(9)
• xe_device_td_flush(9)
• xe_device_assert_mem_access(9)
• Xe Device Wedging(9)
• xe_device_set_wedged_method(9)
• xe_device_declare_wedged(9)
• xe_device_validate_wedged_mode(9)
• xe_wedged_mode_to_string(9)
• xe_device_asid_to_vm(9)

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ok bestie that's the whole page, go forth and barrier your writes properly 💅

mwah 💖 this lil masterpiece lives in ./drivers/gpu/drm/xe and it's dated October 2026 — periodt, that's a wrap 🎀✨