From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Slaby Subject: Re: [PATCH 1/1] PCI: tune up ICH4 quirk for broken BIOSes Date: Thu, 13 Jan 2011 11:07:24 +0100 Message-ID: <4D2ECEDC.4040804@gmail.com> References: <1294327066-23518-1-git-send-email-jslaby@suse.cz> <201101071716.38220.bjorn.helgaas@hp.com> <4D283529.2090909@gmail.com> <201101101140.45501.bjorn.helgaas@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <201101101140.45501.bjorn.helgaas@hp.com> Sender: linux-pci-owner@vger.kernel.org To: Bjorn Helgaas Cc: Jiri Slaby , jbarnes@virtuousgeek.org, linux-pci@vger.kernel.org, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" , Thomas Renninger List-Id: linux-ide@vger.kernel.org On 01/10/2011 07:40 PM, Bjorn Helgaas wrote: > On Saturday, January 08, 2011 02:58:01 am Jiri Slaby wrote: >> 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 ta= bles. >>>>>>> Is that generic information missing, or is it there and Linux i= s >>>>>>> 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 4000-40= 7f. >>>>> >>>>> My point is that BIOS should be telling the OS about GPIO/TCO/etc= =2E >>>>> regions via an ACPI mechanism, and, ideally, we would use that ra= ther >>>>> 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 spa= ce >>>> (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/disa= bled >>>> 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) =E2=80=94 R/W. >> 0 =3D Disable. >> 1 =3D Decode of the I/O range pointed to by the ACPI Base register= is >> enabled, and the ACPI power management function is enabled. Note tha= t >> 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=3Doff was passed to the kernel, there = is >> 0x10 (i.e. ACPI_EN=3D1). However I don't know whether ACPI was disab= led in >> BIOS at that time. >=20 > Checking ACPI_EN before doing anything in the quirk looks like > the simplest thing (if the BIOS actually sets ACPI_EN=3D0 when > it disables ACPI). Unfortunately, they double checked and the BIOS leaves ACPI_EN=3D1 even when ACPI is disabled. =46rom hexdump -Cv /sys/bus/pci/devices/0000\:00\:1f.0/config: 00000040 01 01 00 00 10 00 00 00 00 00 00 00 00 00 01 00 ^base addr^|^-- 4th bit ~ ACPI_EN But I think we still should add the check in any case, the same for GPI= O (there is GPIO_EN) and maybe for newer ICHs. What do you think? The problem is we can't add a quirk based on DMI for this one, since there is no DMI table. I'm out of ideas now. thanks, --=20 js