attn/Attention_Handler.md: Fix MD025 warnings
The following warnings are generated by using markdownlint analysis:
```
attn/Attention_Handler.md:15 MD025/single-title/single-h1 Multiple top-level headings in the same document [Context: "# Overview"]
attn/Attention_Handler.md:41 MD025/single-title/single-h1 Multiple top-level headings in the same document [Context: "# Implementation Details"]
```
Refer to markdown-lint [1] to fix MD025
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/025-single-h1.md
Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I6cd05ec398eabf39f6f870a58103f22530f2cb3b
diff --git a/attn/Attention_Handler.md b/attn/Attention_Handler.md
index b2b4890..d6380d3 100644
--- a/attn/Attention_Handler.md
+++ b/attn/Attention_Handler.md
@@ -1,4 +1,6 @@
-# Introduction
+# Attention Handler
+
+## Introduction
An attention is a hardware, firmware or software alert mechanism used to request
service from an Attention Handler via an attention signal (e.g. a GPIO). An
@@ -12,7 +14,7 @@
executing simultaneously is supported however. There can be at most one instance
of the attention handler service, per attention signal.
-# Overview
+## Overview
The main role of the attention handler is a long running process monitoring the
attention interrupt signal and delegating tasks to external components to aid in
@@ -38,9 +40,9 @@
- checkstop: log an event, call the analyzer, request a system dump and request
a re-ipl of the host.
-# Implementation Details
+## Implementation Details
-## External Components
+### External Components
The attention handler relies on several external components and BMC services for
the handling of attentions. Among these are systemd, dbus, phosphor-logging and
@@ -54,14 +56,14 @@
- phosphor-logging: debug tracing and logging platform events.
- PDBG: querying host hardware.
-## Component Usage
+### Component Usage
- Platform Event Log (PEL) entry creation and debug tracing: phosphor-logging
component.
- Host Transition (re-IPL, MPIPL request): dbus interface.
- Attention handler starting and stopping: systemd.
-## Starting and Stopping
+### Starting and Stopping
The attention handler service is started via the BMC systemd infrastructure when
the host is started. When the attention handler is started it will register
@@ -74,7 +76,7 @@
based on the BMC default restart policy (n-number of restarts in n-seconds
maximum).
-## Attentions
+### Attentions
When the attention signal becomes active the attention handler will begin
handling attentions. Using the PDBG interface the attention handler will query
@@ -85,7 +87,7 @@
Status Register in combination with an associated attention mask register is
used to determine active attentions.
-### Vital Attention
+#### Vital Attention
A vital attention is handled by generating an event log via the phosphor-logging
inteface and then using the dump manager dbus interface to request a hardware
@@ -94,7 +96,7 @@
attention indicates that there was a problem with the Self Boot Engine (SBE)
hardware.
-### Special Attentions
+#### Special Attentions
Three types of attentions, HBTI, PHYPTI and BP, share a single attention status
flag (special attention) in the global interrupt status register. In order to
@@ -104,7 +106,7 @@
for its memory address through the PDBG interface. The request is via a Chip
Operation (chipop) command.
-#### HBTI
+##### HBTI
These attention types are indications from hostboot that an error has occurred
or a shutdown has been requested. When servicing a HBTI the attention handler
@@ -122,13 +124,13 @@
interface. For a TI with EID the attention handler will forgo creating a PEL
entry (hostboot has already done this).
-#### PHYPTI
+##### PHYPTI
These attentions are indications from the hypervisor that an error has occurred.
When servicing a PHYPTI the attention handler will generate a PEL entry and then
request a host MPIPL using the PDBG interface (chipop).
-#### BP (breakpoint)
+##### BP (breakpoint)
These attentions are used to signal to the attention handler that it should
notify the debug agent (e.g. Cronus) that a debug breakpoint has been
@@ -139,7 +141,7 @@
encountered. The attention handler will then go back to listening for
attentions.
-#### Recoverables
+##### Recoverables
These attentions are indications that recoverable errors have been encountered.
These attentions do not generate an attention GPIO event however when servicing
@@ -148,7 +150,7 @@
call the analyzer before requesting a dump or IPL. The check for recoverable
errors is done using the PDBG interface (the Global Interrupt Status Register).
-### Checkstop
+#### Checkstop
These attentions indicate that a hardware error has occurred and further
hardware analyses is required to determine root cause. When servicing a
@@ -157,7 +159,7 @@
will use the dbus interface to request a system dump and upon completetion, or
timeout, will request a re-IPL of the host.
-## Configuration
+### Configuration
Some attention handler behavior can be configured by passing parameters to the
service using the service file or using the command line. Currently the
@@ -169,7 +171,7 @@
- checkstop handling enable/disable, default enable
- special attention default BP/TI, default BP
-## Additional Considerations
+### Additional Considerations
Regardless of the type of special attention the attention handler will always
create at least one PEL entry containing attention handler specific FFDC. In