Date: Tue, 27 Sep 2005 16:35:00 -0700 From: Nate Lawson <nate@root.org> To: Vladimir Grebenschikov <vova@sw.ru> Cc: acpi@freebsd.org, current <current@freebsd.org> Subject: Re: Invalid detection CPU frequency ? Message-ID: <4339D724.3020102@root.org> In-Reply-To: <1127801205.1268.9.camel@localhost> References: <1127801205.1268.9.camel@localhost>
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Vladimir Grebenschikov wrote: > It looks strange but sometimes my notebook start on full-speed (1.7GHz) > and sysctls output looks like: > > dev.cpu.0.freq: 1687 > dev.cpu.0.freq_levels: 1687/-1 1476/-1 1265/-1 1054/-1 843/-1 632/-1 421/-1 210/-1 > dev.acpi_throttle.0.%desc: ACPI CPU Throttling > > And sometimes it starts on low speed (~500 Mhz) > dev.cpu.0.freq: 595 > dev.cpu.0.freq_levels: 595/-1 520/-1 446/-1 371/-1 297/-1 223/-1 148/-1 74/-1 > dev.acpi_throttle.0.%desc: ACPI CPU Throttling > And speed can't be raised by powerd or other. > Looks like it happens when notebook stats or shutdowns on batteries. > Rebooting on AC power cures situation. But anyway - I do not think it is normal. > > Any suggestions ? It's very simple. You have an old notebook that only supports throttling, not SpeedStep or other options. Your BIOS sets the initial speed based on AC line status on boot. If you look at your CPU announcement at the top of dmesg, it will show 595 Mhz or whatever since it uses a simple calibration loop. I might consider always setting 100% in the attach routine for acpi_throttle and p4tcc to get proper probe values. You'll still have a problem if you use the TSC timecounter since it's only calibrated at boot. -- Nate
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