The console passed to TIOCCONS has to be writable, otherwise future
console writes will fail.
This presumably used to work, but in current kernels (see
drivers/tty/tty_io.c:redirected_tty_write) console writes are sent to
vfs_write(device), which checks if the device is writable. A quick look
in the linux git history doesn't show any recent changes to either tty_io
or vfs_write.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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