I apologize if you aren't the person this should be sent to, but I haven't recieved a reply to my last message, so I'm resending with a bit more information. I've also CC'd this message to the linux-kernel mailing list. On linux kernel version 2.5.50+ (I haven't checked below that, 2.4 and 2.4-ac work fine) I am unable to use ACPI features to check battery level, etc. on my laptop. ACPI is enabled in the kernel, and I enter ACPI mode at boot, but it fails to use the ECDT table, and disables ACPI mode before init starts. APM works fine. Output of "dmesg | grep ACPI" for kernel version 2.5.56: ACPI: Wakeup code way too big, will crash on attempt to suspend ACPI: have wakeup address 0xc0001000 ACPI: RSDP (v002 IBM ) @ 0x000f7440 ACPI: XSDT (v001 IBM TP-1E 00000.04416) @ 0x27f6f070 ACPI: FADT (v001 IBM TP-1E 00000.04416) @ 0x27f6f0b4 ACPI: SSDT (v001 IBM TP-1E 00000.04416) @ 0x27f6f168 ACPI: ECDT (v001 IBM TP-1E 00000.04416) @ 0x27f79f87 ACPI: BOOT (v001 IBM TP-1E 00000.04416) @ 0x27f79fd8 ACPI: DSDT (v001 IBM TP-1E 00000.04416) @ 0x00000000 ACPI: BIOS passes blacklist ACPI: MADT not present ACPI: Subsystem revision 20030109 tbxface-0098 [03] acpi_load_tables : ACPI Tables successfully acquired ACPI Namespace successfully loaded at root c05f81fc evxfevnt-0073 [04] acpi_enable : Transition to ACPI mode successful ACPI: Found ECDT ACPI: Could not use ECDT evxfevnt-0118 [06] acpi_disable : ACPI mode disabled ACPI: ACPI tables contain no PCI IRQ routing entries PCI: Invalid ACPI-PCI IRQ routing table utmisc-0720 [02] ut_acquire_mutex : Thread 1 could not acquire Mutex [ACPI_MTX_Memory] AE_BAD_PARAMETER There might be more above this, unfortunately, the dmesg gets cut off before the system finishes booting. If you want, I can compile a lightweight kernel to try to capture any missed messages. By inserting a heapload of printks, I narrowed down the failure in using the ECDT table to the acpi_ns_lookup call made by acpi_ns_get_node_by_path, which is called by acpi_get_handle, which in turn is called by acpi_ec_ecdt_probe in drivers/acpi/ec.c. I can try to narrow it down further, this was all I had the patience for. On a somewhat related note, the prediction of "crashing on suspend" is completely accurate. Fortunately, I never need to suspend this laptop, so I don't really care. Being able to check the battery level would be nice, however. This is an IBM Thinkpad a30p Laptop (that's a single Pentium 3, 684 megs of RAM, one battery, one thermal sensor, one ac adaptor, two case buttons, one internal fan). Attached is a standard BUG_REPORTING set of information, as well as my entime dmesg and .config. -- -Jules Kongslie