If a console was specified by ACPI SPCR table _and_ command line parameters like "console=ttyAMA0" _and_ "earlycon" were specified, then log messages appear twice. This issue was addressed in the patch [1] but the approach was wrong and a revert [2] was suggested. First two patches "printk: fix name/type/scope of preferred_console var" and "printk: rename selected_console -> preferred_console" were sent sent some time ago as one patch "printk: fix name and type of some variables" [3]. They fix name/type/scope of some variables without changing the logic. The real fix is in the second patch. The root cause is that the code traverses the list of specified consoles (the `console_cmdline` array) and stops at the first match. But it may happen that the same console is referred by the elements of this array twice: pl011,mmio,0x87e024000000,115200 -- from SPCR ttyAMA0 -- from command line but in this case `preferred_console` points to the second entry and the flag CON_CONSDEV is not set, so bootconsole is not deregistered. To fix that, match the console against the `console_cmdline` entry pointed by `preferred_console` instead of the first match. v2: - split the patch that renames `selected_console` and `preferred_console` into two patches (Steven Rostedt) - add a comment explaining why we need a separate match to check for preferred_console (Steven Rostedt) - v1 of this patchset changed the logic of console initialization a bit. That could lead to bugs/incompatibilities. Use the exactly the same logic as in the original code. v1: https://lkml.kernel.org/r/20170301161347.4202-1-aleksey.makarov@xxxxxxxxxx [1] https://lkml.kernel.org/r/1485963998-921-1-git-send-email-sudeep.holla@xxxxxxx commit aea9a80ba98a ("tty: serial: pl011: add ttyAMA for matching pl011 console") [2] https://lkml.kernel.org/r/20170301152304.29635-1-aleksey.makarov@xxxxxxxxxx [3] https://lkml.kernel.org/r/1455299022-11641-2-git-send-email-aleksey.makarov@xxxxxxxxxx Aleksey Makarov (3): printk: fix name/type/scope of preferred_console var printk: rename selected_console -> preferred_console printk: fix double printing with earlycon kernel/printk/printk.c | 63 ++++++++++++++++++++++++++++++++------------------ 1 file changed, 41 insertions(+), 22 deletions(-) -- 2.11.1 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
