This is second attempt [1] to get rid of problematic DMA and PM calls in the serial kernel console code. 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. Patches 1-3 are preparatory ones. After previous discussion Tony suggested to add a possibility to detach and attach back kernel console from user space. It's done on patch 4 here. More details on topic are in the commit messages of patches 5 and 6. Patches 7 and 8 are deduplicate follow ups to patch 6. The series has been tested on few Intel platforms. Note, it depends to recently submitted and applied patches in the core console code [2]. [1]: https://lore.kernel.org/patchwork/cover/905632/ [2]: https://lore.kernel.org/lkml/20200203133130.11591-1-andriy.shevchenko@xxxxxxxxxxxxxxx/ Changelog v2: - added possibility to detach and attach back console from userspace (Tony) - reworded commit messages in patches 5 and 6 (Sebastian) - dropped console patch (it had been pushed separately [2]) Andy Shevchenko (8): serial: core: Introduce uart_console_enabled() helper serial: core: Consolidate spin lock initialization code serial: core: use octal permissions on module param serial: core: Allow detach and attach serial device for console serial: 8250_port: Don't use power management for kernel console serial: 8250_port: Disable DMA operations for kernel console serial: 8250_mtk: Remove duplicating code to disable DMA serial: 8250_omap: Remove duplicating code to disable DMA Documentation/ABI/testing/sysfs-tty | 7 ++ drivers/tty/serial/8250/8250_core.c | 9 ++ drivers/tty/serial/8250/8250_mtk.c | 4 - drivers/tty/serial/8250/8250_omap.c | 4 - drivers/tty/serial/8250/8250_port.c | 36 ++++++-- drivers/tty/serial/serial_core.c | 123 ++++++++++++++++++++-------- include/linux/serial_8250.h | 1 + 7 files changed, 134 insertions(+), 50 deletions(-) -- 2.25.0
