Date: Thu, 19 Feb 2009 12:00:38 +0000 From: Rui Paulo <rpaulo@FreeBSD.org> To: Andriy Gapon <avg@icyb.net.ua> Cc: freebsd-acpi@FreeBSD.org Subject: Re: piix4 and C2: patch for BRLD_EN_BM/ACPI_BITREG_BUS_MASTER_RLD Message-ID: <024CB687-4C71-4B57-A105-E4F0BA0DEF32@FreeBSD.org> In-Reply-To: <499D3E2E.7090500@icyb.net.ua> References: <498708FD.9030404@icyb.net.ua> <66885316-6F5B-4C56-BFE0-DBB86E050C99@freebsd.org> <499D3E2E.7090500@icyb.net.ua>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --Apple-Mail-1--960399079 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit On 19 Feb 2009, at 11:10, Andriy Gapon wrote: > on 02/02/2009 17:50 Rui Paulo said the following: >> >> On 2 Feb 2009, at 14:53, Andriy Gapon wrote: >> >>> >>> Another patch for acpi_cpu code related to PIIX4 chipset. >>> >>> We do not support C3 with this chipset and as such we never touch >>> ACPI_BITREG_BUS_MASTER_RLD when running on it. It's also possible >>> (probable) that we never reset ACPI_BITREG_BUS_MASTER_STATUS >>> (because of >>> CPU_QUIRK_NO_BM_CTRL). >>> So, if BIOS configures ACPI_BITREG_BUS_MASTER_RLD to 1 and >>> ACPI_BITREG_BUS_MASTER_STATUS gets set to 1, we would get a >>> situation >>> where the system would always immediately break out of C2 state >>> should >>> we ever attempt to enter it. >>> >>> Actually, ACPI spec says that bus master activity need not break >>> out of >>> C2 state (only interrupts must do that). >>> >>> Given all of the above, it seems to be safe and desired to reset >>> ACPI_BITREG_BUS_MASTER_RLD to zero with this chipset. >>> >>> The patch is successfully tested on a real system that exhibited the >>> above behavior (immediate backout from cx_lowest of C2 to C1). >> >> >> >> Looks ok to me. I no longer have a PIIX4 system to test it, though. >> So, >> if no one raises any objection, I'll commit it to HEAD in a few days. >> >> Andriy, if I forget, please ping me :-) > > Rui, > > may I commit this one now? :) If it builds correctly, yes. Please add Reviewed by: rpaulo (mentor), njl Regards, -- Rui Paulo --Apple-Mail-1--960399079 content-type: application/pgp-signature; x-mac-type=70674453; name=PGP.sig content-description: This is a digitally signed message part content-disposition: inline; filename=PGP.sig content-transfer-encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) iEYEARECAAYFAkmdSeYACgkQfD8M/ASTygLa7QCdFNn3x11SCFI2JNUqM/JcSJpr GbQAn3dKCgTWYr4ylqXi3dGV7VeNW4Yl =ITCf -----END PGP SIGNATURE----- --Apple-Mail-1--960399079--
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