amdgpu_atif_...cklight_caps(9)

💖 NAME 💖

amdgpu_atif_query_backlight_caps — okay so this is the kernel API manual page (section 9, bestie, we're in the deep kernel docs now) and this function's whole job is getting you the min and max backlight input signal. That's it. That's the gig. Slay.

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✨ SYNOPSIS ✨

noinline_for_stack int amdgpu_atif_query_backlight_caps (struct amdgpu_atif *atif );

Literally just one job, one handle, one int coming back at you. Iconic minimalism tbh.

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🎀 ARGUMENTS 🎀

• atif — the acpi handle 💅 that's it, that's the whole parameter list, she's lowkey low-maintenance

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🦋 DESCRIPTION 🦋

So here's the vibe: this function goes and executes the QUERY_BRIGHTNESS_TRANSFER_CHARACTERISTICS ATIF function to figure out the acceptable range of backlight values. Like, what's the actual valid window here, y'know? 🔥

Backlight_caps.caps_valid will be set to true if the query is successful — so that's your little green checkmark, your vibe check passed notification 🫶

The input signals are in range 0-255. No cap, that's the range. 📏

Heads up bestie: this function assumes the display with backlight is the first LCD. Like, it's not out here doing detective work to find which panel — it just assumes. First LCD. Periodt. 👑

Returns 0 on success, error on failure. Classic. 💀

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🌈 SEE ALSO 🌈

The kernel file, for the curious girlies who want to read the source:

• ./drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c

And the whole friend group, fr fr:

• amdgpu_atif_call(9)
• amdgpu_atif_parse_notification(9)
• amdgpu_atif_parse_functions(9)
• amdgpu_atif_verify_interface(9)
• amdgpu_atif_get_notification_params(9)
• amdgpu_atif_get_sbios_requests(9)
• amdgpu_atif_handler(9)
• amdgpu_atcs_call(9)
• amdgpu_atcs_parse_functions(9)
• amdgpu_atcs_verify_interface(9)
• amdgpu_acpi_is_pcie_performance_request_supported(9)
• amdgpu_acpi_is_power_shift_control_supported(9)
• amdgpu_acpi_pcie_notify_device_ready(9)
• amdgpu_acpi_pcie_performance_request(9)
• amdgpu_acpi_power_shift_control(9)
• amdgpu_acpi_smart_shift_update(9)
• amdgpu_acpi_set_uma_allocation_size(9)
• amdgpu_acpi_get_node_id(9)
• amdgpu_acpi_event(9)
• amdgpu_acpi_init(9)
• amdgpu_acpi_fini(9)
• amdgpu_atif_pci_probe_handle(9)
• amdgpu_atcs_pci_probe_handle(9)
• amdgpu_acpi_should_gpu_reset(9)
• amdgpu_acpi_is_s3_active(9)
• amdgpu_acpi_is_s0ix_active(9)

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Okay that's the whole page, bestie, go forth and query those backlight caps 💜✨

Signing off from ./drivers/gpu/drm/amd/amdgpu, dated October 2026 — literally the future, we love to see it 🎀🦋💅