ACK: [trusty] [PATCH 0/3] cpufreq: powernv

Mauricio Faria de Oliveira mauricfo at linux.vnet.ibm.com
Wed Apr 30 15:06:43 UTC 2014


Hi Tim,

>> Note that this also changes behavior for powerpc64-smp. I assume that
>> has been tested ?
>>
>> We also need the attached config patch for packaging.
>
> Thanks for mentioning that.  I completely missed the config patch.
>
> I'll give this another spin and ping back.

First of all, apologies for the extra delayed response.
And thanks for applying the patches w/ the required changes.


Initially I thought of enabling it only for ppc64el, excluding
common -- any other powerpc flavours.
But, given I missed the config patch, this doesn't look like any
position/schedule dates to ask for things. :)

Nonetheless, the code should exit gracefully where non-supported
(i.e., powerpc64-smp on POWER5/Mac hardware), for this check in the
top of init code [1]:

+       power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
+       if (!power_mgt) {
+               pr_warn("power-mgt node not found\n");
+               return -ENODEV;
+       }

.. since that file (actually the 'ibm,opal' dir at all) is not part of 
the device-tree for a POWER5 system (and I can't think of it in Macs),
which is where the powerpc flavours are supposed to run, IIRC [2].

     # grep -m1 ^cpu /proc/cpuinfo
     cpu		: POWER5 (gr)

     # stat /proc/device-tree/ibm,opal/power-mgt
     stat: cannot stat `/proc/device-tree/ibm,opal/power-mgt': No such
     file or directory

Thanks!

[1] drivers/cpufreq/powernv-cpufreq.c
   static int __init powernv_cpufreq_init(void) -> init_powernv_pstates
[2] http://cdimage.ubuntu.com/releases/14.04/release/

-- 
Mauricio Faria de Oliveira
IBM Linux Technology Center





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