diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml index 137a556d92..09eb9b9dfc 100644 --- a/documentation/ref-manual/ref-variables.xml +++ b/documentation/ref-manual/ref-variables.xml @@ -10701,27 +10701,40 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" - If multiple recipes provide an item, this variable - determines which recipe should be given preference. - You should always suffix the variable with the name of the - provided item, and you should set it to the - PN - of the recipe to which you want to give precedence. - Some examples: + If multiple recipes provide the same item, this variable + determines which recipe is preferred and thus provides + the item (i.e. the preferred provider). + You should always suffix this variable with the name of the + provided item. + And, you should define the variable using the preferred + recipe's name + (PN). + Here is a common example: PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto" + + In the previous example, multiple recipes are providing + "virtual/kernel". + The PREFERRED_PROVIDER variable is + set with the name (PN) of the recipe + you prefer to provide "virtual/kernel". + + + + Following are more examples: + PREFERRED_PROVIDER_virtual/xserver = "xserver-xf86" PREFERRED_PROVIDER_virtual/libgl ?= "mesa" For more information, see the - "Metadata (Virtual Providers)" - section in the Yocto Project Concepts Manual. + "Using Virtual Providers" + section in the Yocto Project Development Tasks Manual. - If you set PREFERRED_PROVIDER - for a virtual/* item, then any + If you use a virtual/* item + with PREFERRED_PROVIDER, then any recipe that PROVIDES - that item that is not selected by + that item but is not selected (defined) by PREFERRED_PROVIDER is prevented from building, which is usually desirable since this mechanism is designed to select between mutually