General Questions:
Hello again ACPI gurus! Many thanks for the last tip; I was able to decompile and "fix" the DSDT rather easily using the advice from your responses.
I have a few questions about batteries:
I was looking around the battery driver code last night trying to find out what the battery "alarm" actually does. Unfortuneately (and I only spent a few minutes looking), I wasn't able to easily see what the function of this feature was. I guess my first question is: does it do anything at all? :)
Secondly, would it be beyond of the scope of ACPI for the battery driver to generate ACPI events when the power gets low? Or is there already something like this that exists that I'm missing? I tried watching /proc/acpi/event last as my battery discharged and didn't see any unusual activity.
Thirdly, does the kernel have access to the LED lights on a typical laptop? That is, does it have the ability to ping the LED and make it light up? Or, is that something controlled entirely by hardware? It would be rather neat, I think, to use my "bluetooth" LED (since I don't have bluetooth) in an arbitrary way.
Anyways. :)
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Jeremy L. Moles EmperorLinux 1-888-651-66 www.EmperorLinux.com [email protected] ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl
Quoted 11 lines · Jeremy Moles
Hello again ACPI gurus! Many thanks for the last tip; I was able to decompile and "fix" the DSDT rather easily using the advice from your responses.
I have a few questions about batteries:
I was looking around the battery driver code last night trying to find out what the battery "alarm" actually does. Unfortuneately (and I only spent a few minutes looking), I wasn't able to easily see what the function of this feature was. I guess my first question is: does it do anything at all? :)
The 'alarm' feature implemented in Linux is actually mapped to the _BTP (battery trip point) of the ACPI specification. Section 10.2.2.4 of this spec indicates that a notify must be issued when the battery remaining capacity crosses this alarm level (either falling below or rising above).
When the battery receives this notification, it dispatches a battery event, which shows up in /proc/acpi/events. What action is taken on this event is up to whatever userspace application you are using. I myself have configured acpid so that when a battery event is read, AND the system is on battery power, AND the remaining capacity is below the alarm level, the system automatically suspends (using swsusp2).
Quoted 6 lines
Secondly, would it be beyond of the scope of ACPI for the battery driver to generate ACPI events when the power gets low? Or is there already something like this that exists that I'm missing? I tried watching
/proc/acpi/eventlast as my battery discharged and didn't see any unusual activity.
As per the stuff above, there is already stuff there. However, it only works through the _BTP functionality. If this functionality is not implemented in the DSDT -- or if the alarm level is set crazy low -- then you lose the capability to get advanced warning of low-power situations.
Quoted 6 lines
Thirdly, does the kernel have access to the LED lights on a typical laptop? That is, does it have the ability to ping the LED and make it light up? Or, is that something controlled entirely by hardware? It would be rather neat, I think, to use my "bluetooth" LED (since I don't have bluetooth) in an arbitrary way.
This really depends on the laptop in question. Do you by any chance have an Acer? My Acer TM4502 has an unused bluetooth LED/button, and I think there *might* be a way to control it through the BIOS (see recent posts by Johan Vromans).
cheers,
Rich
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