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Re: suggested APM documentation modifications
In article <20080503152007.3dd8acc4.jklowden%schemamania.org@localhost>,
James K. Lowden <netbsd-docs%netbsd.org@localhost> wrote:
>I read http://www.netbsd.org/docs/power-mgmt/ recently and thought it
>could be made clearer. My version, below, add no new information; I
>simply think it's a better exposition. Submitted for your consideration.
>=== snip ===
>This document describes NetBSD's support for hardward-provided power
>management facilities, including the Advanced Power Management (APM)
>features found in most modern laptops. Most of the information is
>i386-specific because NetBSD does not support power management on other
>architecutures as of this writing.
>The Basics of Power Management (top)
>Laptop power management centers around Advanced Power Management. APM is a
>BIOS-provided interface to the hardware power management features. NetBSD
>receives APM events (such as suspend requests) or makes power management
>requests or queries (such as the current battery level).
>APM specifies two power-saving modes: standby and suspend. The precise
>meaning of each mode at the hardware level depends on the laptop being
>used. [ed: "depends on the BIOS implementation"?] "standby" typically
>means a light sleep; it consumes more power and is quicker to restore from
>APM timers for standby and suspend mode are usually configured in the
>BIOS. When the BIOS determines the machine has been "idle" long enough, it
>requests that the operating system enter one of the power-saving modes.
>NetBSD has three components that support APM.
>1. The kernel driver is the interface to the APM BIOS.
>2. The apm daemon, apmd, interfaces with the APM kernel driver and runs
>the userland event scripts.
>3. The command line program, apm, interfaces to apmd and can be used to
>query battery level or initiate a system suspend.
>APM events generally flow as follows:
>1. The APM BIOS queues a standby/suspend request.
>2. The APM kernel driver gets the request event the next time it polls
>the APM BIOS (typically once per second) and queues the standby/suspend
>request to the apm daemon.
>3. The apm daemon determines whether or not to accept this request, based
>on the current power source and the daemon configuration. If the request
>is accepted, it performs any standby/suspend activities, then sends the
>accept/reject notice back to the kernel driver.
>4. The kernel driver sends the accept/reject notice to the APM BIOS.
>5. If the event request was accepted, the APM BIOS places the hardware in
>the specified mode.
>=== unsnip ===
>"power-saving" is hyphenated because they're two words describing a third
>(mode). Same with "i386-specific [information]".
>In the current document, no special typeface is used consistently to set
>off program names e.g. apm and apmd. I think they should be highlighted
>somehow, perhaps with a typewriter font.
>I haven't looked into how the document is maintained. If the above
>changes are accepted (in some form), I could contribute patches in the
diffs would be nice.
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