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Date: Tue, 22 Jul 2008 14:33:06 -0400 From: Jeff Garzik <jeff@...zik.org> To: "H. Peter Anvin" <hpa@...or.com> CC: "Luis R. Rodriguez" <mcgrof@...il.com>, linux kernel <linux-kernel@...r.kernel.org>, "H. Peter Anvin" <hpa@...nel.org>, Ivan Seskar <Seskar@...lab.rutgers.edu>, jfm3 <jfm3@...lab.rutgers.edu>, Sujith <m.sujith@...il.com> Subject: Re: Bug on 2.6.26 - x86 VIA Nehemiah CentaurHauls processor cannot boot H. Peter Anvin wrote: > Jeff Garzik wrote: >>> >>> Thanks for taking a look at this. So well, it would be a >>> misconfiguration bug by the distribution then to try to support a >>> generic 686 kernel wihtout GENERIC then. >> >> Well, it may be intentional -- some distros simply exclude support for >> the lower-volume VIA processors, since that might imply building their >> "generic 686 kernel" sans CMOV and some other instructions, and >> changing the compiler's instruction scheduling to something less >> optimal for the majority. :/ >> > > X86_GENERIC shouldn't disable CMOV? I said "generic 686 kernel" not a specific Kconfig option (for reasons stated below), which is a bit different. > We're only referring specifically to the family == 6 VIA processors here. To be specific, I was merely saying that VIA processors where c->x86_model==6 may lack CMOV. I have not kept track of what current Kconfig options will set, but in the past it was quite easy to build a "generic 686 kernel" that required CMOV and thus excluded these VIA processors. Distros in the past often wound up intentionally -not- supporting some of these VIA processors, because they did not want to create a non-CMOV kernel. (This policy obviously excluded older x86 as well) If these things have been addressed recently (< 12-18 months) then all good. Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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