Date: Sat, 14 Oct 2017 22:26:02 +0100 From: tech-lists <tech-lists@zyxst.net> To: freebsd-hardware@freebsd.org, freebsd-mobile@freebsd.org Subject: Re: problems getting AMD C-70 APU working with powerd/cpufreq Message-ID: <20171014212602.GB92751@acer.zyxst.net> In-Reply-To: <20171014215317.K34192@sola.nimnet.asn.au> References: <20171013123721.GA27736@acer.zyxst.net> <20171014215317.K34192@sola.nimnet.asn.au>
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Hi, thanks for taking the time to look at this, On Sat, Oct 14, 2017 at 10:36:02PM +1100, Ian Smith wrote: >On Fri, 13 Oct 2017 13:37:21 +0100, tech-lists wrote: > > Hi, > > > > I have a netbook with amd c-70 cpu and am trying to get powerd > > to work with it. Will this chip not work with cpufreq/powerd? > >Perhaps not. oh well!! > > > system: FreeBSD 11.1-STABLE #0 r324342 > > > > # sysctl debug.cpufreq.verbose=1 > > debug.cpufreq.verbose: 0 -> 1 > >This shows that cpufreq was alreasy loaded. It's in the GENERIC kernel. >Have a good browse through cpufreq(4). I can't comment about earlier versions of FreeBSD, but this sysctl is present on 11.1-stable without cpufreq loaded. I'm using a modified kernel - modified to the extent that superfluous stuff has been removed, because this machine is hardware-challenged. Without cpufreq loaded, the following sysctls are present: # sysctl -a | grep cpufreq debug.cpufreq.verbose: 0 debug.cpufreq.lowest: 0 # uname -i ACER # cat /sys/amd64/conf/ACER |grep cpufreq # # cat /boot/loader.conf amdtemp_load="YES" # I've known this machine has had issues with cpufreq for a while, but this is the first time I've sat down to try work out why. This is one of the reasons why cpufreq isn't in my kernel. which is why I was able to > > # kldload cpufreq > > # no message (I set debug.cpufreq.verbose to 1 in order to hopefully see more output) > > dev.acpi_perf.1.%parent: cpu1 > > dev.acpi_perf.0.%parent: cpu0 > >These are interesting. In cpufreq(4) you'll see acpi_perf is one of the >absolute frequency control drivers, presumably used (see also in dmesg) >because the expected driver for AMD processors, powernow, did not attach >- though your verbose dmesg shows nothing about any failure/s to attach. > > > dev.cpu.1.cx_method: C1/hlt C2/io > > dev.cpu.1.cx_usage_counters: 237351 1893186 > > dev.cpu.1.cx_usage: 11.14% 88.85% last 156us > > dev.cpu.1.cx_lowest: C2 > >At least you're getting plentiful use of C2 state, though I'm not aware >how much power saving that might buy you on that AMD CPU. Not a lot! ;) One of the reasons I'm interested in powerd/cpufreq is that I beleive it can make turbo kick in. Apparently this chip has a turbo mode @1.333GHz. might be wrong about that though. >So, there's no dev.cpu.0.freq nor dev.cpu.0.freq_levels - therefore >powerd has nothing to work with. Its (misleading?) message doesn't mean >cpufreq not loaded, but that the sysctls powerd relies upon don't exist. [...] >Nothing in any of those suggests that this cpu has any other frequency >available than 1000MHz, which seems quite bizarre to me. Of course it's >possible FreeBSD hasn't been taught to recognise this particular cpu. > >You haven't disabled anything in $BIOS related to power or freq control? The bios has only a very limited number of options for this machine - possibly by design as the machine is a netbook. Options for overclocking are not present at all. >The cpuid output has a heading "Advanced Power Management Feature Flags" >near the bottom, but none are shown. yeah, odd that >Hope someone else has something more useful to offer, and thanks for >mailing me those files when my browser was deemed too old for your site. thanks again for your help -- J.
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