Linux on the Samsung V25
What is this about?
I recently bought myself a new notebook computer and was quite
disappointed at the APM implementation, which only seems to implement
the suspend mode and not much else. In particular it does not provide me
with any information on the current state of the battery. ACPI power
management is even worse, at least with the kernels I have tried (2.4.20
from SuSE Linux 8.2 and vanilla 2.5.74). To work around this problem I
have written a userspace tool for reading the battery information
directly from the embedded controller as specified in the ACPI DSDT, as
well as a kernel patch that replaces the APM BIOS call usually used for
obtaining the information with direct hardware access.
What machines does it work on?
I have tested the tool and the kernel patch on my Samsung V25 and have
received reports that it works fine on the Samsung V20 and Dell Latitude X200 as well.
I have disassembled some DSDTs I have found on the net and concluded that
it should also work on several other recent Samsung
WARNING: Before trying to use
the kernel patch you should run the userspace tool and make sure it
returns sane results.
The userspace tool: directec.c
Note that this needs to be run as (setuid) root.
The kernel patch: linux-2.4.20-v25apm.patch
This patch was made against the SuSE Linux 8.2 kernel sources, but
should apply to most recent kernels. Apart from replacing the call to
APM_FUNC_GET_STATUS it also maps standby to suspend as the real standby
mode hangs my machine.
Information I need
Please write to email@example.com if
- have successfully run the userspace tool and/or the kernel patch
on a notebook other than the Samsung V20/V25 or Dell Latitude X200.
- know what the SWBE, DCBE, RFON, SPDI, B1SE, B1TM and B1NM fields
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