On 01/08/2011 01:16 AM, Bjorn Helgaas wrote: > On Friday, January 07, 2011 04:29:00 pm Jiri Slaby wrote: >> On 01/08/2011 12:03 AM, Bjorn Helgaas wrote: >>> On Friday, January 07, 2011 01:44:35 pm Jiri Slaby wrote: >>>> On 01/06/2011 08:24 PM, Bjorn Helgaas wrote: >>>>> Theoretically, ACPI tells us about the GPIO/TCO/etc. regions in a >>>>> generic way via namespace devices or something in the static tables. >>>>> Is that generic information missing, or is it there and Linux is >>>>> ignoring it? If we're ignoring it, I'd rather fix that. >>>> >>>> It works for most boxes I would say. Try to google for "claimed by ICH4 >>>> ACPI/GPIO/TCO", it reports sane ranges like 0400-047f or 4000-407f. >>> >>> My point is that BIOS should be telling the OS about GPIO/TCO/etc. >>> regions via an ACPI mechanism, and, ideally, we would use that rather >>> than reading the address out of chipset-dependent registers. >>> >>> Even though PMBASE says the ACPI registers occupy 128 bytes from >>> 0x100-0x17f, it's likely there's no actual conflict between the >>> last 16 bytes and the IDE device. >> >> I wouldn't say so. According to the datasheet 0x60-0x7f of the space >> (i.e. 0x160-0x17f here) is for TCO registers. There: >> 0x10 -- Software IRQ Generation Register (i.e. 0x170) >> 0x11-0x1f -- reserved (0x171-0x17f) >> >> So at least 0x170 should be conflicting. Unless TCO is unused/disabled >> and not mapped there at all. May be that the case? > > Maybe. All your patch does is avoid reserving this 0x100-0x1f7 > region; it doesn't actually *move* anything. And the IDE device > apparently works at the 0x170 compatibility address. So the > ICH ACPI stuff is still at 0x100-0x17f, so apparently they don't > conflict or maybe the ICH ACPI stuff is disabled. If the box > doesn't even have ACPI, I suppose there would be no reason to > have the ACPI registers enabled. Is there something in ICH > that tells us whether they're enabled? Hmm, there is: bit 4: ACPI Enable (ACPI_EN) â R/W. 0 = Disable. 1 = Decode of the I/O range pointed to by the ACPI Base register is enabled, and the ACPI power management function is enabled. Note that the APM power management ranges (B2/B3h) are always enabled and are not affected by this bit. at 0x44 in the bridge conf space. So we should definitely check the value. I don't have the actual value in that register when ACPI is disabled in BIOS. From the run where acpi=off was passed to the kernel, there is 0x10 (i.e. ACPI_EN=1). However I don't know whether ACPI was disabled in BIOS at that time. >>> ACPI probably reports this region via the FADT (the GPE PM register >>> blocks) and possibly a PNP0C02 device. These will probably report >>> something that doesn't conflict with the legacy IDE ports, i.e., a >>> subset of the 0x100-0x17f range. >>> >>> Ooooh, I notice in the bugzilla that something's wrong with SMBIOS >>> (comment 29) and ACPI is disabled because we couldn't find the >>> RSDP (dmesg in comment 27). What sort of machine is this, anyway? >>> We didn't find PNPBIOS, either. >> >> Hmm, it looks like some old crap. What exact information you would like >> to know? I've just asked if ACPI is not disabled in BIOS. There should >> be no machine without ACPI running still in the 21st century, I think. > > I'm just wondering if the machine actually does have ACPI, but > there's some Linux problem related to finding the tables. If it's > really old enough, that wouldn't be so surprising, but I see USB > and gigabit NIC hardware, so it's not truly ancient. The box is: http://www.xembedded.com/content/vme/processors/xvme-690.php and has ACPI, but the user disabled ACPI (I don't know why yet). thanks, -- js -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
