Re: [PATCH] handle fadt->si_cmd == 0
From: Takayoshi Kochi <hidden>
Date: 2003-06-09 00:29:38
Hi Jesse, From: jbarnes-sJ/iWh9BUns@public.gmane.org (Jesse Barnes) Subject: [ACPI] [PATCH] handle fadt->si_cmd == 0 Date: Fri, 6 Jun 2003 10:17:30 -0700 Message-ID: [off-list ref]
In reading the spec, it looks like if a particular ACPI implementation leaves fadt->si_cmd equal to 0, that means the platform doesn't support system management mode, which seems legal. I needed this patch for my system. With the patch applied, I'm able to see /proc/acpi and the interpreter appears to start. Is this legal?
Once there was an exactly same discussion, and the current implementation is correct. As you wrote, the meaning of value 0 in smi_cmd field in the FADT is clarified in the ACPI spec 2.0 and this is implemented in acpi_hw_set_mode(). But in any case, SCI_ENABLE bit in PM1 control register should be set correctly, reflecting the system state. If your platform specifies smi_cmd is 0 and SCI_ENABLE is 'enabled', the ACPI subsystem won't try to call acpi_hw_set_mode() to enable ACPI mode (as it's already in ACPI mode). IIRC, once there was the same workaround in the ia64 patch for some (prototype?) HP machines.
quoted hunk
--- /usr/tmp/TmpDir.30375-0/linux/drivers/acpi/hardware/hwacpi.c_1.10 Fri Jun 6 10:24:23 2003 +++ linux/drivers/acpi/hardware/hwacpi.c Tue Jun 3 10:48:31 2003@@ -180,6 +180,10 @@ ACPI_FUNCTION_TRACE ("Hw_get_mode"); + /* If there's no smi_cmd port, then it's ACPI only hw */ + if (!acpi_gbl_FADT->smi_cmd) + return_VALUE (ACPI_SYS_MODE_ACPI); + status = acpi_get_register (ACPI_BITREG_SCI_ENABLE, &value, ACPI_MTX_LOCK); if (ACPI_FAILURE (status)) { return_VALUE (ACPI_SYS_MODE_LEGACY); -------------------------------------------------------This SF.net email is sponsored by: Etnus, makers of TotalView, The best thread debugger on the planet. Designed with thread debugging features you've never dreamed of, try TotalView 6 free at www.etnus.com. _______________________________________________ Acpi-devel mailing list Acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org https://lists.sourceforge.net/lists/listinfo/acpi-devel
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