drm: document drm_property_enum.value for bitfields
When a property has the type DRM_MODE_PROP_BITMASK, the value field stores a bitshift, not a bitmask, which can be surprising. Signed-off-by: Simon Ser <contact@emersion.fr> Cc: Leandro Ribeiro <leandro.ribeiro@collabora.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com> Link: https://patchwork.freedesktop.org/patch/msgid/NUZTPTKKZtAlDhxIXFB1qrUqWBYKapkBxCnb1S1bc3g@cp3-web-033.plabs.ch
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@ -31,7 +31,6 @@
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/**
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* struct drm_property_enum - symbolic values for enumerations
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* @value: numeric property value for this enum entry
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* @head: list of enum values, linked to &drm_property.enum_list
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* @name: symbolic name for the enum
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*
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* decoding for each value. This is used for example for the rotation property.
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*/
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struct drm_property_enum {
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/**
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* @value: numeric property value for this enum entry
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*
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* If the property has the type &DRM_MODE_PROP_BITMASK, @value stores a
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* bitshift, not a bitmask. In other words, the enum entry is enabled
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* if the bit number @value is set in the property's value. This enum
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* entry has the bitmask ``1 << value``.
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*/
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uint64_t value;
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struct list_head head;
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char name[DRM_PROP_NAME_LEN];
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