From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 115FDC54EE9 for ; Tue, 13 Sep 2022 22:50:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229739AbiIMWun (ORCPT ); Tue, 13 Sep 2022 18:50:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229686AbiIMWuk (ORCPT ); Tue, 13 Sep 2022 18:50:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8751165270 for ; Tue, 13 Sep 2022 15:50:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id CBF6061627 for ; Tue, 13 Sep 2022 22:50:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5672C433D6; Tue, 13 Sep 2022 22:50:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663109438; bh=+dYScZf8oC85BzrYt8r36FW8HDb2ksPxKtaCWZJR+8g=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=ec/X4JvAF185ieQqqv6tEfOsX/oi8QsRt+Jxw+IewfNoctV8rxBTgvni3+FflANaU WO5PlgmQxs9eYz9tPYJ676/+yt1JCaOO5ql2QL5NlPM7Xq5NwZS7F/MJp7KkPK9bFq s7mB/UPEAcCEfYWJALD3+5+4BrmlfogrTwm6AHBeiU0UM+rfToS1U1XgfxarZGdmdi CQQP00NE7/Qn6vTK5nZJo27iM+0lW0o8C5E9PqQzLtPX0To/YN5YbyMbhxs0lRJ5wV J9jYTpXJmWqE9g+GcooDfSaSjVl0iYnAyQLWRt1B+3WVmVLW7EvjkX1RRdgo2xGeGM TveaBLAVXfpqw== Date: Tue, 13 Sep 2022 17:50:36 -0500 From: Bjorn Helgaas To: Mateusz =?utf-8?Q?Jo=C5=84czyk?= Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Ira W . Snyder" Subject: Re: [PATCH v2 08/10] x86/Kconfig: make CONFIG_PCI_CNB20LE_QUIRK depend on X86_32 Message-ID: <20220913225036.GA631462@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220911084711.13694-9-mat.jonczyk@o2.pl> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 11, 2022 at 10:47:09AM +0200, Mateusz Jończyk wrote: > I was unable to find a good description of the ServerWorks CNB20LE > chipset. However, it was probably exclusively used with the Pentium III > processor (this CPU model was used in all references to it that I > found where the CPU model was provided: dmesgs in [1] and [2]; > [3] page 2; [4]-[7]). > > As is widely known, the Pentium III processor did not support the 64-bit > mode, support for which was introduced by Intel a couple of years later. > So it is safe to assume that no systems with the CNB20LE chipset have > amd64 and the CONFIG_PCI_CNB20LE_QUIRK may now depend on X86_32. > > Additionally, I have determined that most computers with the CNB20LE > chipset did have ACPI support and this driver was inactive on them. > I have submitted a patch to remove this driver, but it was met with > resistance [8]. Only because removing the driver appeared to have no demonstrated benefit and risked breaking old machines. Making this depend on X86_32 seems plausible to me. > [8] Bjorn Helgaas, "Re: [PATCH] x86/pci: drop ServerWorks / Broadcom > CNB20LE PCI host bridge driver" > https://lore.kernel.org/lkml/20220318165535.GA840063@bhelgaas/T/ > > Signed-off-by: Mateusz Jończyk > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: Dave Hansen > Cc: x86@kernel.org > Cc: "H. Peter Anvin" > Cc: Ira W. Snyder > Cc: Bjorn Helgaas > --- > v2: make CONFIG_PCI_CNB20LE_QUIRK depend on X86_32 > (previously only help text and description were changed) > upgrade short description. > > arch/x86/Kconfig | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index fdfe8b7e895a..31f778b0cd0b 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -2739,13 +2739,21 @@ config MMCONF_FAM10H > depends on X86_64 && PCI_MMCONFIG && ACPI > > config PCI_CNB20LE_QUIRK > - bool "Read CNB20LE Host Bridge Windows" if EXPERT > - depends on PCI > + bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT > + depends on X86_32 && PCI > help > Read the PCI windows out of the CNB20LE host bridge. This allows > PCI hotplug to work on systems with the CNB20LE chipset which do > not have ACPI. > > + The ServerWorks (later Broadcom) CNB20LE was a chipset designed > + most probably only for Pentium III. > + > + To find out if you have such a chipset, search for a PCI device with > + 1166:0009 PCI IDs, for example by executing > + lspci -nn | grep '1166:0009' > + The code is inactive if there is none. > + > There's no public spec for this chipset, and this functionality > is known to be incomplete. > > -- > 2.25.1 >