ACPI / debugger: Add kernel flushing support

The AML debugger can be used to dump the runtime value of a named object, which is useful for remote debugging issues. The batch mode of the AML debugger allows the debugger functionalities to be integrated into the scripts.

Currently, when the batch mode is used, the userspace tool needs to flush the output (logs/prompts) remained in the kernel output buffer in order not to mess up the result of the executed batch mode command, this is implemented in an inefficient way in the userspace by polling the IO and reading everything out.
However, the input needn't be flushed as the command input should have already been flushed by the signals and won't be passed to acpi_os_get_line() due to an error return value.

This patch introduces a kernel space flushing support, so that userspace can invoke ioctl() to request the driver to drop old outputs.

Lv Zheng (3):
ACPI / debugger: Add kernel flushing support tools/power/acpi/acpidbg: Use new flushing mechanism tools/power/acpi/acpidbg: Add multi-commands support in batch mode

 drivers/acpi/acpi_dbg.c                  |   85 +++++++++++++++++++++--
 include/linux/acpi.h                     |    1 +
 include/uapi/linux/acpi-ioctls.h         |   21 ++++++
 tools/power/acpi/tools/acpidbg/acpidbg.c |  110 +++++++++++++++++-------------
 4 files changed, 165 insertions(+), 52 deletions(-)
 create mode 100644 include/uapi/linux/acpi-ioctls.h

1.7.10