[PATCH] radeon: Make PM info available to all, not just debug users

[Christian König]

On 04.06.2012 10:44, Lauri Kasanen wrote:
> On Sun, 03 Jun 2012 12:54:30 +0200
> Christian König<deathsimple at vodafone.de>  wrote:
>
>>> This moves the pm_info file from debugfs to next to the other two power files.
>>>
>>> Requested by several users at Phoronix.
>>>
>>> PS: Please CC me. Also please be gentle, it's my first step in kernel-land ;)
>> Hui? What should this be good for?
>>
>> Sysfs files are for setting driver parameters, like the power management
>> method or profile currently in use. One major advantage of sysfs is the
>> strict rules for a permanent and machine usable interface, for example
>> it is mandatory to only specify one parameter per sysfs file.
>>
>> Debugfs on the other hand should be used for human readable
>> informations, e.g. the printing the current clocks in a human readable
>> form. Also you don't need a debug build or turn on any other debugging
>> facility to get those information, just take a look under
>> "sys/kernel/debug/dri/*".
> I have no such dir, /sys/kernel/debug. The fact you have it means you have CONFIG_DEBUGFS enabled and mounted.
>
>> So the code is actually quite valid as it is.
> First, the current location is illogical, and several users have complained about it. This info should be right next to where it is tweaked, ie right next to power_profile and power_method. That is where it's expected to be by users.
>
> Secondly, checking the clocks is absolutely not a debug operation. Therefore requiring a debug option (CONFIG_DEBUGFS) to see this info is plain wrong.. This info needs to be available to all users, including those on production kernels without such debug options.
>
> --
>
> So the issue is the location of the info, not the format. I'd be more than happy to split it into six files (default_core_clock, current_core_clock...) that each offer just a kHz number, just like the cpufreq scaling_cur_freq do. Would that be preferable?
Yeah, that sounds like a start, and also only register those files if 
the clock in question is really available, e. g. integrated chipsets 
doesn't have a memory clock for example.

But I have my doubts that it would be accepted easily, cause for debugfs 
we can pretty much pump every information in there we want, while sysfs 
files must maintain a more or less stable API for setting system 
parameters, see Documentation/sysfs-rules.txt.

Christian.