Re: Detecting x86 LAPIC timer frequency from CPUID data

2019-04-19 Thread Jacob Pan
On Fri, 19 Apr 2019 22:52:01 +0200 (CEST) Thomas Gleixner wrote: > On Fri, 19 Apr 2019, Jacob Pan wrote: > > On Fri, 19 Apr 2019 10:57:10 +0200 (CEST) > > Thomas Gleixner wrote: > > > On Fri, 19 Apr 2019, Daniel Drake wrote: > > > > 0x7F vs 0x7FFF, is that intentional? > > > > >

Re: Detecting x86 LAPIC timer frequency from CPUID data

2019-04-19 Thread Thomas Gleixner
On Fri, 19 Apr 2019, Jacob Pan wrote: > On Fri, 19 Apr 2019 10:57:10 +0200 (CEST) > Thomas Gleixner wrote: > > On Fri, 19 Apr 2019, Daniel Drake wrote: > > > 0x7F vs 0x7FFF, is that intentional? > > > > I don't think so. Looks like a failed copy and paste. Cc'ed Jacob, he > > might know

Re: Detecting x86 LAPIC timer frequency from CPUID data

2019-04-19 Thread Jacob Pan
On Fri, 19 Apr 2019 10:57:10 +0200 (CEST) Thomas Gleixner wrote: > On Fri, 19 Apr 2019, Daniel Drake wrote: > > On Fri, Apr 19, 2019 at 6:30 AM Thomas Gleixner > > wrote: > > >Time Stamp Counter/Core Crystal Clock Information (0x15): > > > TSC/clock ratio = 168/2 > > > nominal

Re: Detecting x86 LAPIC timer frequency from CPUID data

2019-04-19 Thread Daniel Drake
On Fri, Apr 19, 2019 at 6:30 AM Thomas Gleixner wrote: >Time Stamp Counter/Core Crystal Clock Information (0x15): > TSC/clock ratio = 168/2 > nominal core crystal clock = 0 Hz > >Processor Frequency Information (0x16): > Core Base Frequency (MHz) = 0x834 (2100) > Co

Re: Detecting x86 LAPIC timer frequency from CPUID data

2019-04-19 Thread Thomas Gleixner
On Fri, 19 Apr 2019, Daniel Drake wrote: > On Fri, Apr 19, 2019 at 6:30 AM Thomas Gleixner wrote: > >Time Stamp Counter/Core Crystal Clock Information (0x15): > > TSC/clock ratio = 168/2 > > nominal core crystal clock = 0 Hz > > > >Processor Frequency Information (0x16): > >

Re: Detecting x86 LAPIC timer frequency from CPUID data

2019-04-18 Thread Thomas Gleixner
On Thu, 18 Apr 2019, Thomas Gleixner wrote: > On Wed, 17 Apr 2019, Daniel Drake wrote: > > > The CPUID.0x16 leaf provides "Bus (Reference) Frequency (in MHz)". > > > > In the thread "No 8254 PIT & no HPET on new Intel N3350 platforms > > causes kernel panic during early boot" we are exploring way

Re: Detecting x86 LAPIC timer frequency from CPUID data

2019-04-18 Thread Thomas Gleixner
On Wed, 17 Apr 2019, Daniel Drake wrote: > The CPUID.0x16 leaf provides "Bus (Reference) Frequency (in MHz)". > > In the thread "No 8254 PIT & no HPET on new Intel N3350 platforms > causes kernel panic during early boot" we are exploring ways to have > the kernel avoid using the PIT/HPET IRQ0 tim

Detecting x86 LAPIC timer frequency from CPUID data

2019-04-16 Thread Daniel Drake
The CPUID.0x16 leaf provides "Bus (Reference) Frequency (in MHz)". In the thread "No 8254 PIT & no HPET on new Intel N3350 platforms causes kernel panic during early boot" we are exploring ways to have the kernel avoid using the PIT/HPET IRQ0 timer in more cases, and Thomas Gleixner suggested that