gt-64260 Question

Milliorn Gary-rxcr80 Gary.Milliorn at
Wed Nov 26 07:59:43 EST 2003

owner-linuxppc-embedded at wrote:
> Benjamin Davis wrote:
>> Errata 9 of
>> talks about some issues with QACK,
> Okay.
>> I further noticed how in arch/ppc/platform/pmac_feature.c, in
>>     probe_uninorth: if (uninorth_rev < 0x11) {
>>         actrl = UN_IN(UNI_N_ARB_CTRL) &
>>         ~UNI_N_ARB_CTRL_QACK_DELAY_MASK; actrl |= ((uninorth_rev <
>>             3) ? UNI_N_ARB_CTRL_QACK_DELAY105 :
>>         UN_OUT(UNI_N_ARB_CTRL, actrl);
>> It would appear to me that a QACK delay is being set by communication
>> with the uninorth.  I will say now though this is my first
>> experiance with the kernel. I was kinda thinking they might have
>> gotten around the errata by extending the delay of the QACK.  This
>> QACK is the system saying it is time to get out of nap, and snoop.
> I don't see any reference in the 64260 manual that lets you control
> this.  Are you sure that you need to nap/snooze?  IOW, are you sure
> you're not solving a problem you don't have?

The 64260 does not implement the QACK power management protocol; most
boards just tie it off or connect it only to the COP/JTAG header.

So, you probably needn't worry about it.

Gary Milliorn, Motorola       phone: 512 996.7066
PowerPC Development Platforms email: mailto:Gary.Milliorn at
Computing Platform Division

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