Kernel console is sensitive to any kind of complex work needed to print out anything on it. One such case is emergency print during Oops.
This series proposes to disable runtime PM and DMA operations on 8250 serial console. More detailed explanation why is provided in patch 2. The series has been in our internal trees for years already with no problems observed. Andy Shevchenko (3): console: introduce ->exit() callback serial: 8250_port: Don't use power management for kernel console serial: 8250_port: Disable DMA operations for kernel console drivers/tty/serial/8250/8250_core.c | 9 +++++++++ drivers/tty/serial/8250/8250_port.c | 27 ++++++++++++++++++++++----- include/linux/console.h | 1 + include/linux/serial_8250.h | 1 + kernel/printk/printk.c | 3 +++ 5 files changed, 36 insertions(+), 5 deletions(-) -- 2.17.0
