Some explanation of /etc/default/grub, with example

2 files changed, 81 insertions, 3 deletions

diff --git a/en-US/Fedora_Multiboot_Guide.xml b/en-US/Fedora_Multiboot_Guide.xml
index c8ebc13..a97b5be 100644
--- a/en-US/Fedora_Multiboot_Guide.xml
+++ b/en-US/Fedora_Multiboot_Guide.xml
@@ -11,7 +11,8 @@
   <xi:include href="Free_Space.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
 	<xi:include href="GRUB.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
 	<xi:include href="BIOS.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
-	<xi:include href="UEFI.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
+  <xi:include href="UEFI.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
+  <xi:include href="boot_arguments.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
 	<xi:include href="Revision_History.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
 	<index />
 </article>
diff --git a/en-US/GRUB-configuration.xml b/en-US/GRUB-configuration.xml
index 2bc66e4..386f57b 100644
--- a/en-US/GRUB-configuration.xml
+++ b/en-US/GRUB-configuration.xml
@@ -13,7 +13,7 @@
   <formalpara>
     <title><filename>/etc/default/grub</filename></title>
     <para>
-      Configuration for GRUB itself is defined in <filename>/etc/default/grub</filename>.  The default options used when creating new entries for Fedora can also  be found here.
+      Configuration for GRUB itself is defined in <filename>/etc/default/grub</filename>.  The default options used when creating new entries for Fedora can also be found here.
     </para>
   </formalpara>
   <formalpara>
@@ -25,7 +25,7 @@
   <formalpara>
     <title><filename class="directory">/boot</filename></title>
     <para>
-      The <filename class="directory">/boot</filename></title> directory contains Fedora's kernel and <systemitem class="filesystem">initramfs</systemitem>.
+      The <filename class="directory">/boot</filename> directory contains Fedora's kernel and <systemitem class="filesystem">initramfs</systemitem>.
     </para>
   </formalpara>
     <para>
@@ -37,5 +37,82 @@
       This directory is only found on UEFI systems, and is within the UEFI System Partition. Both GRUB configuration files and the GRUB executable can be found in <filename class="directory">/boot/efi/EFI</filename>.
     </para>
   </formalpara>
+  <section id="GRUB-configuration-permanent_arg">
+    <title>Permanently adding to Fedora boot entries</title>
+    <para>
+      The options that GRUB passes to Fedora when booting are generated from the discovered filesystems and from the value of <parameter>GRUB_CMDLINE_LINUX</parameter> in <filename>/etc/default/grub</filename>.
+    </para>
+    <para>
+      Adding a parameter to the end of <parameter>GRUB_CMDLINE_LINUX</parameter> and regenerating <filename>grub.cfg</filename> will apply the parameter to all current and future Fedora boot entries.
+    </para>
+    <example id="GRUB-configuration-permanent_arg-backlight_example">
+      <title>In practice: Fixing backlight issues with kernel parameters</title>
+      <para>
+        Some laptops have problems with the display backlight using the default configuration. The screen might be too bright, too dim, flicker, or even appear to be completely black.
+      </para>
+      <para>
+        The issue can often be resolved by directing the system to prefer vendor-specific drivers for the backlight using the <parameter>acpi_backlight=vendor</parameter> parameter.
+      </para>
+      <procedure>
+        <step>
+          <para>
+            With root permissions, open the file <filename>/etc/default/grub</filename>.
+            <screen>
+              <command>nano /etc/default/grub</command>
+              <computeroutput>
+                GRUB_TIMEOUT=0
+                GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
+                GRUB_DEFAULT=saved
+                GRUB_DISABLE_SUBMENU=true
+                GRUB_TERMINAL_OUTPUT="console"
+                GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 $([ -x /usr/sbin/rhcrashkernel-param ] &amp;&amp; /usr/sbin/rhcrashkernel-param || :) vconsole.keymap=us rhgb quiet"
+                GRUB_DISABLE_RECOVERY="true"
+              </computeroutput>
+            </screen>
+          </para>
+        </step>
+        <step>
+          <para>
+            Add the parameter to the end of <parameter>GRUB_CMDLINE_LINUX</parameter> and save the file.
+            <screen>
+              <computeroutput>
+                GRUB_TIMEOUT=0
+                GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
+                GRUB_DEFAULT=saved
+                GRUB_DISABLE_SUBMENU=true
+                GRUB_TERMINAL_OUTPUT="console"
+                GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 $([ -x /usr/sbin/rhcrashkernel-param ] &amp;&amp; /usr/sbin/rhcrashkernel-param || :) vconsole.keymap=us rhgb quiet acpi_backlight=vendor"
+                GRUB_DISABLE_RECOVERY="true"
+              </computeroutput>
+            </screen>
+          </para>
+        </step>
+        <step>
+          <para>
+            Regenerate the GRUB configuration to apply the new changes.
+          </para>
+          <substeps>
+            <step>
+              <para>
+                For BIOS systems:
+                <screen>
+                  <command>grub2-mkconfig -o /boot/grub/grub2.cfg</command>
+                </screen>
+              </para>
+            </step>
+            <step>
+              <para>
+                For UEFI systems:
+                <screen>
+                  <command>grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg</command>
+                </screen>
+              </para>
+            </step>
+          </substeps>
+        </step>
+      </procedure>
+    </example>
+  </section>
+
 </section>