Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/i915: Document the GMCH_CTRL register a bit
The actual GMCH_CRTL lives in the host bridge aka. device 0,
but device 2 has a read-only mirror on i85x/i865+. Document
that fact.
Also remove the ancient tales about where the defines are used.
Those haven't been true in a long time.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20251208182637.334-20-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
+5
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include/drm/intel/i915_drm.h
+5
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include/drm/intel/i915_drm.h
···
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extern struct resource intel_graphics_stolen_res;
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/*
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* The Bridge device's PCI config space has information about the
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* fb aperture size and the amount of pre-reserved memory.
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* This is all handled in the intel-gtt.ko module. i915.ko only
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* cares about the vga bit for the vga arbiter.
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* The bridge device's (device 0) PCI config space has information
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* about the fb aperture size and the amount of pre-reserved memory.
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*/
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/* device 2 has a read-only mirror */
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#define SNB_GMCH_CTRL 0x50
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#define SNB_GMCH_GGMS_SHIFT 8 /* GTT Graphics Memory Size */
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#define SNB_GMCH_GGMS_MASK 0x3
···
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#define BDW_GMCH_GMS_SHIFT 8
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#define BDW_GMCH_GMS_MASK 0xff
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/* device 2 has a read-only mirror from i85x/i865 onwards */
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#define I830_GMCH_CTRL 0x52
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#define I830_GMCH_GMS_MASK (0x7 << 4)
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#define I830_GMCH_GMS_LOCAL (0x1 << 4)