On (05/09/17 10:29), Sabrina Dubroca wrote: [..] > That's caused a change of behavior in my qemu setup, with this cmdline > > root=/dev/sda1 console=ttyS1 console=ttyS0 > > Before, the kernel logs appeared on ttyS1, and I logged in with ttyS0 > (with my setup, ttyS1 is a file and ttyS0 is unix socket). Now, the > kernel logs go to ttyS0. I need to swap the two console= parameters to > restore behavior. > > There might be some other problem (in qemu?) though, because adding > console=tty0 anywhere on that cmdline makes the logs appear on both > tty0 and one ttyS* (but only one of them, and the ordering of the > ttyS* matters). thanks for the report. so we have ttyS1 first and ttyS0 last. after commit in question, register_console() iterates console_cmdline in reverse order so we see ttyS0 first, then we hit `if (newcon->index < 0)' condition, set newcon to ttyS0, because we iterate in reverse order now, and break out. so we enable ttyS0, instead of ttyS1. previously, we iterated console_cmdline from index 0 and saw ttyS1 first. so the same `if (newcon->index < 0)' condition would set newcone to ttyS1, and, thus, we would enable ttyS1, not ttyS0. -ss -- 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
