Date: Thu, 26 Mar 2009 14:37:31 +0000 From: Bruce Cran <bruce@cran.org.uk> To: John Baldwin <jhb@freebsd.org> Cc: Daniel =?utf-8?Q?Dvo=C5=99=C3=A1k?= <dandee@hellteam.net>, freebsd-acpi@freebsd.org Subject: Re: kern/108581: [sysctl] sysctl: hw.acpi.cpu.cx_lowest: Invalid argument Message-ID: <20090326143731.0d2b7711@gluon.draftnet> In-Reply-To: <200903260937.51028.jhb@freebsd.org> References: <200903200030.n2K0U3iG011009@freefall.freebsd.org> <20090325223914.4387eeae@gluon.draftnet> <200903260937.51028.jhb@freebsd.org>
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On Thu, 26 Mar 2009 09:37:50 -0400 John Baldwin <jhb@freebsd.org> wrote: > No, the code is doing things differently on purpose (though I'm not > completely sure why). For _CST it sets cpu_cx_count to the maximum > Cx level supported by any CPU in the system. For non-_CST it sets it > to the maximum Cx level supported by all CPUs in the system. I think > it is correct for cpu_cx_count to always start at 0 and only be > bumped up to a higher setting. Setting it to 3 would be very wrong > for the _CST case as I've seen CPUs that support C4. =46rom briefly reading through the specifications I'd assumed the maximum power state was C3. =20 I had thought the _CST block was wrong because in acpi_cpu_global_cx_lowest_sysctl it validates the new value against cpu_cx_count; if one CPU has a lower cx state than the others, then won't this tell the other CPUs to use an unsupported state? --=20 Bruce Cran
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