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authorfishsoupisgood <github@madingley.org>2019-04-29 01:17:54 +0100
committerfishsoupisgood <github@madingley.org>2019-05-27 03:43:43 +0100
commit3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch)
tree65ca85f13617aee1dce474596800950f266a456c /roms/u-boot/doc/README.silent
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Initial import of qemu-2.4.1HEADmaster
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+The config option CONFIG_SILENT_CONSOLE can be used to quiet messages
+on the console. If the option has been enabled, the output can be
+silenced by setting the environment variable "silent".
+
+- CONFIG_SILENT_CONSOLE_UPDATE_ON_SET
+ When the "silent" variable is changed with env set, the change
+ will take effect immediately.
+
+- CONFIG_SILENT_CONSOLE_UPDATE_ON_RELOC
+ Some environments are not available until relocation (e.g. NAND)
+ so this will make the value in the flash env take effect at
+ relocation.
+
+The following actions are taken if "silent" is set at boot time:
+
+ - Until the console devices have been initialized, output has to be
+ suppressed by testing for the flag "GD_FLG_SILENT" in "gd->flags".
+
+ - When the console devices have been initialized, "stdout" and
+ "stderr" are set to "nulldev", so subsequent messages are
+ suppressed automatically. Make sure to enable "nulldev" by
+ #defining CONFIG_SYS_DEVICE_NULLDEV in your board config file.
+
+ - When booting a linux kernel, the "bootargs" are fixed up so that
+ the argument "console=" will be in the command line, no matter how
+ it was set in "bootargs" before. If you don't want the linux command
+ line to be affected, define CONFIG_SILENT_U_BOOT_ONLY in your board
+ config file as well, and this part of the feature will be disabled.