Re: Wakeup from a PCI device

[Frank Helms <frank.helms@amd.com>]

Hi Bruce,

I am in favor of adding a wake-up pin.  It seems reasonable that a portable 
PC would be expected to wake-up with a modem ring even if the PCI bus was
powered down for power management reasons.

Thanks,
Frank P. Helms 8/14/96
frank.helms@amd.com 
- Note: The views expressed are my own, and not necessarily those of AMD. -

At 10:25 AM 8/14/96 PDT, Bruce Young wrote:
>     Many of you may recall a thread back in April talking about how a PCI 
>     device could initiate a wakeup for a powered down system. The proposal 
>     that I had made as a part of the initial work I did on PCI Power 
>     Management defined the standard INTx# signals as the mechanism to 
>     accomplish this. After much discussion and working through as many of 
>     the technical issues as we could, the PCI Power Management Working 
>     Group has decided to request that a reserved pin be assigned for this 
>     purpose. While the technical details are quite involved, the overall 
>     reason is that we decided that we did not want to eliminate the 
>     possibility of a device in a powered-down slot initiating a wakeup and 
>     the only electrically feasible way to do this while maintaining 
>     compatibility with older PCI cards is to use a new pin. 
>     
>     The impact of this should be minimal. Most PCI peripherals don't need 
>     to initiate a wakeup and therefore have no need to add the pin. 
>     Chipsets that want to support wakeup will, in general, have dedicated 
>     inputs for wakeup from other devices (e.g. Lid open or suspend switch) 
>     that shared for this new signal as well. The only devices which will 
>     need to add a pin are those that have a need to wake a "sleeping" 
>     system which will typically be comm and network cards. I realize that 
>     this can be a significant impact on those devices but we could not 
>     solve all the technical issues related to using the INTx# pins. 
>     
>     I want to emphasize that this is not final and no-one should start 
>     designing Si with this new pin yet. The ECR will go through the 
>     standard PCI SIG process of approval which consists of Working Group 
>     approval (in this case the protocol working group), Steering Committee 
>     approval and then a 30 day review period for the entire SIG. I am 
>     posting this to highlight the issue and try to understand how this 
>     will be received by the entire PCI design community. I believe that a 
>     dialog early can help minimize the problems later in the process.
>     
>     So what do you think? Is this a non-issue that everyone agrees a 
>     separate pin for wakeup is a good idea? Or is everyone dead-set 
>     against adding a pin on principle!?
>     
>     -Bruce Young, Intel Corporation 
>     PCI SIG Power Management Working Group Chairman 
>
>
>
________________________________________________________
 Frank P. Helms 
 frank.helms@amd.com
-The opinions expressed are my own and not necessarily those of AMD.-
0
hW