From: Preeti U Murthy <preeti@linux.vnet.ibm.com>
To: Shreyas B Prabhu <shreyas@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v4 3/3] powerpc/powernv: Introduce sysfs control for fastsleep workaround behavior
Date: Tue, 14 Apr 2015 14:01:41 +0530 [thread overview]
Message-ID: <552CD06D.9070701@linux.vnet.ibm.com> (raw)
In-Reply-To: <552CCB77.1000307@linux.vnet.ibm.com>
On 04/14/2015 01:40 PM, Shreyas B Prabhu wrote:
>
>>>
>>> By default, fastsleep_workaround_state = dynamic. In this case, workaround
>>> is applied/undone everytime the core enters/exits fastsleep.
>>>
>>> fastsleep_workaround_state = applyonce. In this case the workaround is
>>> applied once on all the cores and never undone. This can be triggered by
>>> echo applyonce > /sys/devices/system/cpu/fastsleep_workaround_state
>>
>> I was wondering if we really need such an elaborate design for this
>> sysfs file. Why not a sysfs file called fastsleep_workaround_apply_once,
>> which is set to '0' by default and the only value that it can take is
>> '1' ? The name easily implies that the workaround is applied only once
>> if it is set. I can see that this can cut down a good chunk of code from
>> this patch. I just didn't find too much value in having so much code for
>> a simple 'on' knob.
>
> I was considering something similar too. But then moved to this format
> as I thought this was unambiguous. Also moving to a binary attribute
> will reduces code only in show_fastsleep_workaround_state which I don't
> feel is much.
> That said, if you feel strongly about it, I can change it to the format
> you suggested.
It cuts down two of your data structures:
fastsleep_workaround_avail_states[] and the enum and the parsing of the
input string in store_fastsleep_workaround_state() too.
Regards
Preeti U Murthy
>
> Thanks,
> Shreyas
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
next prev parent reply other threads:[~2015-04-14 8:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-14 1:56 [PATCH v4 0/3] powerpc: powernv: Fastsleep workaround behavior Shreyas B. Prabhu
2015-04-14 1:56 ` [PATCH v4 1/3] powerpc: Fix cpu_online_cores_map to return only online threads mask Shreyas B. Prabhu
2015-04-14 1:56 ` [PATCH v4 2/3] powerpc/powernv: Move cpuidle related code from setup.c to new file Shreyas B. Prabhu
2015-04-14 5:07 ` Preeti U Murthy
2015-04-14 1:56 ` [PATCH v4 3/3] powerpc/powernv: Introduce sysfs control for fastsleep workaround behavior Shreyas B. Prabhu
2015-04-14 5:59 ` Preeti U Murthy
2015-04-14 8:10 ` Shreyas B Prabhu
2015-04-14 8:31 ` Preeti U Murthy [this message]
2015-04-14 8:27 ` Preeti U Murthy
2015-04-15 6:05 ` Shreyas B Prabhu
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