freebsd-dev/sys/x86
Andriy Gapon ec6faf94c4 add support for console resuming, implement it for uart, use on x86
This change adds a new optional console method cn_resume and a kernel
console interface cnresume.  Consoles that may need to re-initialize
their hardware after suspend (e.g., because firmware does not care to do
it) will implement cn_resume.  Note that it is called in rather early
environment not unlike early boot, so the same restrictions apply.
Platform specific code, for platforms that support hardware suspend,
should call cnresume early after resume, before any console output is
expected.

This change fixes a problem with a system of mine failing to resume when
a serial console is used.  I found that the serial port was in a strange
configuration and an attempt to write to it likely resulted in an
infinite loop.

To avoid adding cn_resume method to every console driver, CONSOLE_DRIVER
macro has been extended to support optional methods.

Reviewed by:	imp, mav
MFC after:	3 weeks
Differential Revision: https://reviews.freebsd.org/D15552
2018-05-29 16:16:24 +00:00
..
acpica add support for console resuming, implement it for uart, use on x86 2018-05-29 16:16:24 +00:00
bios sys/x86: further adoption of SPDX licensing ID tags. 2017-11-27 15:11:47 +00:00
cpufreq cpufreq: Remove error-prone table terminators in favor of automatic sizing 2018-04-14 03:15:05 +00:00
include Cleanups related to debug exceptions on x86. 2018-05-22 00:45:00 +00:00
iommu Don't include DMAR map entry zone items in kernel dumps. 2018-02-18 16:03:50 +00:00
isa ANSIfy sys/x86 2018-03-17 01:40:09 +00:00
pci Add ISA PNP tables to ISA drivers. Fix a few incidental comments. 2018-01-29 00:22:30 +00:00
x86 fix x86 UP build broken by r334204, TSC resynchronization 2018-05-29 16:03:53 +00:00
xen xen/pvh: allocate dbg_stack 2018-05-24 10:22:57 +00:00