Merge tag 'kgdb-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt...

[tomoyo/tomoyo-test1.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f793951..52e63f3 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1190,6 +1190,11 @@
                        This is designed to be used in conjunction with
                        the boot argument: earlyprintk=vga
 
+                       This parameter works in place of the kgdboc parameter
+                       but can only be used if the backing tty is available
+                       very early in the boot process. For early debugging
+                       via a serial port see kgdboc_earlycon instead.
+
        edd=            [EDD]
                        Format: {"off" | "on" | "skip[mbr]"}
 
@@ -2112,6 +2117,21 @@
                         kms, kbd format: kms,kbd
                         kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
 
+       kgdboc_earlycon=        [KGDB,HW]
+                       If the boot console provides the ability to read
+                       characters and can work in polling mode, you can use
+                       this parameter to tell kgdb to use it as a backend
+                       until the normal console is registered. Intended to
+                       be used together with the kgdboc parameter which
+                       specifies the normal console to transition to.
+
+                       The name of the early console should be specified
+                       as the value of this parameter. Note that the name of
+                       the early console might be different than the tty
+                       name passed to kgdboc. It's OK to leave the value
+                       blank and the first boot console that implements
+                       read() will be picked.
+
        kgdbwait        [KGDB] Stop kernel execution and enter the
                        kernel debugger at the earliest opportunity.