drivers/gpu/drm/i915/i915_gmch.c

File Facts

System

Linux kernel

Corpus path

drivers/gpu/drm/i915/i915_gmch.c

Extension

.c

Size

3835 bytes

Lines

142

Domain

Driver Families

Bucket

drivers/gpu

Inferred role

Driver Families: implementation source

Status

source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/pnp.h
• drm/drm_managed.h
• drm/drm_print.h
• drm/intel/pci_config.h
• i915_drv.h
• i915_gmch.h

Detected Declarations

• function i915_gmch_bridge_release
• function i915_gmch_bridge_setup
• function mchbar_reg
• function intel_alloc_mchbar_resource
• function i915_gmch_bar_setup
• function i915_gmch_bar_teardown

Annotated Snippet

if (IS_I915G(i915) || IS_I915GM(i915)) {
			u32 deven_val;

			pci_read_config_dword(i915->gmch.pdev, DEVEN,
					      &deven_val);
			deven_val &= ~DEVEN_MCHBAR_EN;
			pci_write_config_dword(i915->gmch.pdev, DEVEN,
					       deven_val);
		} else {
			u32 mchbar_val;

			pci_read_config_dword(i915->gmch.pdev, mchbar_reg(i915),
					      &mchbar_val);
			mchbar_val &= ~1;
			pci_write_config_dword(i915->gmch.pdev, mchbar_reg(i915),
					       mchbar_val);
		}
	}

	if (i915->gmch.mch_res.start)
		release_resource(&i915->gmch.mch_res);
}

Annotation

• Immediate include surface: `linux/pnp.h`, `drm/drm_managed.h`, `drm/drm_print.h`, `drm/intel/pci_config.h`, `i915_drv.h`, `i915_gmch.h`.
• Detected declarations: `function i915_gmch_bridge_release`, `function i915_gmch_bridge_setup`, `function mchbar_reg`, `function intel_alloc_mchbar_resource`, `function i915_gmch_bar_setup`, `function i915_gmch_bar_teardown`.
• Atlas domain: Driver Families / drivers/gpu.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.