[PATCH v2 0/2] serial: core: fix broken console after suspend

From: Lukasz Majczak
Date: Wed Apr 05 2023 - 07:19:22 EST


This is v2 of a patch[1].
v1->v2:
* Fixed typos in commit message
* Tested[2] patch "serial: core: preserve cflags, ispeed and ospeed" on all
current LTS kernels (4.14, 4.19, 5.4, 5.10, 5.15, 6.1) and on top of
6.3-rc5 with positive results - console was working after resume
* During tests another issue was observed on 6.1+ - FIFO not enabled after
resume - and an additional change was needed ("serial: core: enable
FIFO after resume")
* Test procedure:
1) ensure the console output is ok
2) suspend device with "echo freeze > /sys/power/state"
(/sys/module/printk/parameters/console_suspend == N)
3) resume device and check the console output
4) suspend device with "echo freeze > /sys/power/state"
(/sys/module/printk/parameters/console_suspend == Y)
5) resume device and check the console output

[1] https://lore.kernel.org/lkml/20230301075751.43839-1-lma@xxxxxxxxxxxx/
[2] Test platforms: PC with i5-8400 + GB H370M D3H
HP Elite c1030 Chromebook Enterprise i5-10310U

Lukasz Majczak (2):
serial: core: preserve cflags, ispeed and ospeed
serial: core: enable FIFO after resume

drivers/tty/serial/serial_core.c | 57 +++++++++++++++-----------------
1 file changed, 27 insertions(+), 30 deletions(-)

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2.40.0.577.gac1e443424-goog