On Tue, 13 Dec 2005 18:26:51 +0000 Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote: > On Tue, Dec 13, 2005 at 10:14:17AM -0800, Randy Dunlap wrote: > > > 7. Most important: What good does the ACPI interface do/add? > > What I mean is that acpi_get_child() in scsi_acpi_find_channel() > > always returns a handle value of 0, so it doesn't get us > > any closer to determining the ACPI address (_ADR) of the SATA > > devices. The acpi_get_devices() technique in my patch (basically > > walking the ACPI namespace, looking at all "devices") is the > > only way that I know of doing this, but I would certainly > > like to find a better way. > > When the PCI bus is registered, acpi walks it and finds the appropriate > acpi handle for each PCI device. This is shoved in the > firmware_data field of the device structure. Later on, we register the > scsi bus. As each item on the bus is added, the acpi callback gets > called. If it's not an endpoint, scsi_acpi_find_channel gets called. > We're worried about the host case. The host number will correspond to > the appropriate _ADR underneath the PCI device that the host is on, so > we simply get the handle of the PCI device and then ask for the child > with the appropriate _ADR. That gives us the handle for the device, and > returning that sticks it back in the child's firmware_data field. > > At least, that's how it works here. If acpi_get_child always returns 0 > for you, then it sounds like something's going horribly wrong. Do you > have a copy of the DSDT? Thanks for the explanation. The 136 KB DSDT is at: http://www.xenotime.net/linux/SATA/acpitbl.out . --- ~Randy - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
