Re: ISA -> ISA_ (Re: [GIT PATCH] ACPI patches for 2.6.25-rc6)

From: Alexey Starikovskiy
Date: Wed Mar 26 2008 - 15:22:03 EST


Bjorn Helgaas wrote:
On Wednesday 26 March 2008 11:24:41 am Alexey Starikovskiy wrote:
Bjorn Helgaas wrote:
I'm curious about how this works. I disassembled the DSDT from
http://bugzilla.kernel.org/show_bug.cgi?id=4773 (I attached the disassembly
at http://bugzilla.kernel.org/attachment.cgi?id=15448&action=view), and
the _PRT contains "_SB" and "ISA" (no trailing underscores):

Package (0x04)
{
0x000DFFFF, 0x00, \_SB.PCI0.ISA.LNKA, 0x00
}

But by the time we get to acpi_pci_irq_add_entry(), we've added the
underscores somewhere (see
http://bugzilla.kernel.org/attachment.cgi?id=15423&action=view):

0000:00:0d[A] -> \_SB_.PCI0.ISA_.LNKA

I don't know where this happens, but it certainly confused me, and
it seems like it could lead to other bugs.
ACPI is supposed to add trailing underscore for pad all names to 4 bytes.
So ISA will be padded to ISA_.

The questions are "where does this happen?" and "why does it not
apply to other things like asus_acpi.c?"
1. drivers/acpi/namespace/nsutils.c:419
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