Re: Linux 2.6.30-rc8 [also: VIA Support]

["Michael S. Zick" <lkml@morethan.org>]

On Fri June 5 2009, Harald Welte wrote:
> On Thu, Jun 04, 2009 at 12:27:07PM -0500, Michael S. Zick wrote:
> > On Thu June 4 2009, Linus Torvalds wrote:
> > > 
> > > Side note: is it more stable if you disable the VIA speedstep thing 
> > > (whatever it's called (ok, google tells me it's called "TwinTurbo" and 
> > > "Advanced PowerSaver")?
> > >
> > 
> > The e_powersave code.
> 
> that is only for the early C7, as I've been told by Centaur.  C7-M should
> definitely support the ACPI states.  So better to disable both.
> 
> > It was a fixed-speed kernel build that first hit the 4 hour up-time mark.
> > I just reposted that build today (the -09143lk).
> 
> did you actually check if the power transitions are on longer happening?
> 

No - without a /sys...cpufreq directory I don't know how to do that.
But the machine is performing exactly as if it was at a fixed speed of 600Mhz.

Much different than when e_powersaver is included - -

Also, the e_powersaver stats look reasonable when compared with test loads
running, so although this may be an acpi controlled system, e_powersaver
"thinks" it has control (and does make a difference in performance).
It is not that hard to tell subjectively the difference between 0.4Ghz
and 1.2Ghz.

Mike
> > For want of a documented JTAG port...
> 
> there is JTAG on the CPU, but only for EXTEST/INTEST, i.e. access to the actual
> signal lanes for making sure all the BGA pads are soldered and actually connect
> to the right signals of the next component on the board.  There is no embedded
> ICE or anything of that sort.  Also, your board most likely doesn't have JTAG
> on an accessible connector, since it's out of mass production.
>