Date: Thu, 12 Sep 2019 17:41:59 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 240475] [PATCH]: Add support for CPUID 0x16 in tsc_freq_cpuid() (TSC clock) Message-ID: <bug-240475-227-tV7YhfstWB@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-240475-227@https.bugs.freebsd.org/bugzilla/> References: <bug-240475-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D240475 --- Comment #3 from Neel Chauhan <neel@neelc.org> --- This patch is based upon an existing Linux commit: https://github.com/torvalds/linux/commit/604dc9170f2435d27da5039a3efd757dce= adc684 In the commit message: Skylake, Kabylake and all variants of those two chipsets report a crystal frequency of zero, however we can calculate the crystal clock speed by condidering data from CPUID.0x16. This method correctly distinguishes between the two crystal clock frequencies present on different Skylake X variants that caused headaches before. As the calculations do not quite match the previously-hardcoded values in some cases (e.g. 23913043Hz instead of 24MHz), TSC refinement is enabled on all platforms where we had to calculate the crystal frequency in this way. This is also true on my system. I will post two verbose dmesgs: one without any patches, and one with this patch (which also has drm-kmod and Vladimir Kondratyev's iichid loaded). --=20 You are receiving this mail because: You are the assignee for the bug.=
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