Re: device driver for the SGI system clock, mmtimer

[Robert Picco <Robert.Picco@hp.com>]

Bjorn Helgaas wrote:

>On Thursday 16 September 2004 10:32 am, Christoph Lameter wrote:
>  
>
>>On Thu, 16 Sep 2004, Bjorn Helgaas wrote:
>>    
>>
>>>Christoph Lameter wrote:
>>>      
>>>
>>>>The timer hardware was designed around the multimedia timer specification by Intel
>>>>but to my knowledge only SGI has implemented that standard. The driver was written
>>>>by Jesse Barnes.
>>>>        
>>>>
>>>As far as I can see, drivers/char/hpet.c talks to the same hardware.
>>>HP sx1000 machines (and probably others) also implement the HPET.
>>>      
>>>
>>The Intel Multimedia Standard is a earlier and different timer spec.
>>    
>>
>
>I have a spec that's labelled "IA-PC Multimedia Timers", preliminary
>draft of June 2000, revision 0.97, which looks like the one mentioned
>in your patch.
>
>I also have something labelled "IA-PC HPET (High Precision Event
>Timers) Specification", draft of February 2002, revision 0.98,
>which is what drivers/char/hpet.c supports.
>
>I admit I haven't compared them in great detail, but they certainly
>*look* like they're close enough that the same driver could support
>both, and the 0.98 revision history only mentions fairly cosmetic
>changes (like the name :)).
>
>Is there something specific that drivers/char/hpet.c expects that
>your hardware doesn't implement?
>
>  
>
Look at HPET revision history.  Specifically 0.98 01/20/2002
    * Product name changed: from Multimedia Timer to HPET (High 
Precision Event Timer)

Bob