Re: [PATCH RFC 3/3] MIPS: AR7: ensure the port type's FCR value is used

On 14 November 2017 at 12:02, James Hogan [off-list ref] wrote:

On Sun, Oct 29, 2017 at 04:27:21PM +0100, Jonas Gorski wrote:

quoted

Since commit aef9a7bd9b67 ("serial/uart/8250: Add tunable RX interrupt
trigger I/F of FIFO buffers"), the port's default FCR value isn't used
in serial8250_do_set_termios anymore, but copied over once in
serial8250_config_port and then modified as needed.

Unfortunately, serial8250_config_port will never be called if the port
is shared between kernel and userspace, and the port's flag doesn't have
UPF_BOOT_AUTOCONF, which would trigger a serial8250_config_port as well.

This causes garbled output from userspace:

[    5.220000] random: procd urandom read with 49 bits of entropy available
ers
   [kee

Fix this by forcing it to be configured on boot, resulting in the
expected output:

[    5.250000] random: procd urandom read with 50 bits of entropy available
Press the [f] key and hit [enter] to enter failsafe mode
Press the [1], [2], [3] or [4] key and hit [enter] to select the debug level

Fixes: aef9a7bd9b67 ("serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
---
I'm not sure if this is just AR7's issue, or if this points to a general
issue for UARTs used as kernel console and login console with the "fixed"
commit.

Thanks. Given nobody seems to have objected, I've applied to my
mips-fixes branch, with stable tag for 3.17+.

Hmm, I don't see it in
https://git.kernel.org/pub/scm/linux/kernel/git/jhogan/mips.git/log/?h=mips-fixes
- did you maybe forget to push?


Regards
Jonas