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 notebooks.

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

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