| Message ID | 20130226161049.GA9303@kahuna (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
On Tue, Feb 26, 2013 at 8:10 AM, Nishanth Menon <nm@ti.com> wrote: > On 16:55-20130226, Rafael J. Wysocki wrote: >> >> It says that in "Introduction", but it would be clearer if the title of the >> doc was something like "Operating Performance Points (OPP) Library". Nishanth? > > Yes indeed. Will the following help? I can post it as an official patch > if the direction is proper Yes, this will definitely help. I didn't even find it in the introduction (Rafael is correct that it is indeed there), because it's hard to see when you don't know what to scan for and it's in a big block of text. I am also happy to note that it is in the Kconfig help and single-line description. Which wasn't true for the new SATA_ZPODD ("Zero Power ODD" - what the heck is ODD?) which was another new entry I wondered about. It turns out that ODD is an odd TLA for "Optical Disk Drive". I'm sure it makes perfect sense if you are a SATA person, but it sure doesn't for any normal human being, even otherwise highly technical ones. Aaron, Tejun, Jeff, can I ask you to also not use specialized TLA's without explaining them? Especially in help text and "documentation", it's very unhelpful to have TLA's that aren't common. We don't have to explain *all* TLA's, since there's a lot that really are rather widespread. But there's a big difference between something like CPU or TLB that have been in generic literature for decades, wrt OPP and ODD that are specialized terms used inside a very particular group and haven't been around for very long either. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Ugh. Forgot to actually add the ODD people to the list...
Linus
On Tue, Feb 26, 2013 at 8:27 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Tue, Feb 26, 2013 at 8:10 AM, Nishanth Menon <nm@ti.com> wrote:
>> On 16:55-20130226, Rafael J. Wysocki wrote:
>>>
>>> It says that in "Introduction", but it would be clearer if the title of the
>>> doc was something like "Operating Performance Points (OPP) Library". Nishanth?
>>
>> Yes indeed. Will the following help? I can post it as an official patch
>> if the direction is proper
>
> Yes, this will definitely help. I didn't even find it in the
> introduction (Rafael is correct that it is indeed there), because it's
> hard to see when you don't know what to scan for and it's in a big
> block of text.
>
> I am also happy to note that it is in the Kconfig help and single-line
> description. Which wasn't true for the new SATA_ZPODD ("Zero Power
> ODD" - what the heck is ODD?) which was another new entry I wondered
> about.
>
> It turns out that ODD is an odd TLA for "Optical Disk Drive". I'm sure
> it makes perfect sense if you are a SATA person, but it sure doesn't
> for any normal human being, even otherwise highly technical ones.
>
> Aaron, Tejun, Jeff, can I ask you to also not use specialized TLA's
> without explaining them? Especially in help text and "documentation",
> it's very unhelpful to have TLA's that aren't common.
>
> We don't have to explain *all* TLA's, since there's a lot that really
> are rather widespread. But there's a big difference between something
> like CPU or TLB that have been in generic literature for decades, wrt
> OPP and ODD that are specialized terms used inside a very particular
> group and haven't been around for very long either.
>
> Linus
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On Tue, Feb 26, 2013 at 08:28:56AM -0800, Linus Torvalds wrote: > > Aaron, Tejun, Jeff, can I ask you to also not use specialized TLA's > > without explaining them? Especially in help text and "documentation", > > it's very unhelpful to have TLA's that aren't common. > > > > We don't have to explain *all* TLA's, since there's a lot that really > > are rather widespread. But there's a big difference between something > > like CPU or TLB that have been in generic literature for decades, wrt > > OPP and ODD that are specialized terms used inside a very particular > > group and haven't been around for very long either. Aye aye, captain. One interesting bit, for me (and possibly Aaron too), ODD is much more closer to an everyday term. For some reason, at least in Korea, ODD is a popular term. For exmple, the likes of newegg would use it along with CPU, SSD or VGA to label product categories, so that probably is why ODD never registered as something which needed explanation, and that we all are pretty familiar with ATA jargons. Anyways, yeah, no ODDs without expansion nearby. Thanks.
On Tue, Feb 26, 2013 at 8:37 AM, Tejun Heo <tj@kernel.org> wrote: > > One interesting bit, for me (and possibly Aaron too), ODD is much more > closer to an everyday term. For some reason, at least in Korea, ODD > is a popular term. For exmple, the likes of newegg would use it along > with CPU, SSD or VGA to label product categories Just checked newegg in the US. If you look for "ODD" here, you get a very odd response. For example, Fairly Odd Parents By Nickelodeon Bubble Bath 7 Oz Model #: 692237016543 shows up fairly high. Not an actual optican disk drive in sight, but there are DVD's and "ODD bay"s there. Searching for "optical disk drive" works. But then I never see anything called "ODD" anywhere. I did find it in the "Technical Specifications" for one of the drives, though. Anyway, in the US it is definitely not a common term for normal people. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Feb 26, 2013 at 08:47:30AM -0800, Linus Torvalds wrote:
> Anyway, in the US it is definitely not a common term for normal people.
Googling "odd" doesn't give anything on optical drives on the first
page. On the other hand, >70% is about optical drives on naver.com.
The discrepancy is funny given that most computer terms in Korea come
from US. Maybe it's because the character combination "odd" doesn't
have any other meaning. Even then, I'm surprised there's no optical
drive result at all in the first page of google search. Definitely
doesn't seem like a common term in US.
On 02/26/2013 11:58 AM, Tejun Heo wrote: > On Tue, Feb 26, 2013 at 08:47:30AM -0800, Linus Torvalds wrote: >> Anyway, in the US it is definitely not a common term for normal people. > > Googling "odd" doesn't give anything on optical drives on the first > page. On the other hand, >70% is about optical drives on naver.com. > The discrepancy is funny given that most computer terms in Korea come > from US. Maybe it's because the character combination "odd" doesn't > have any other meaning. Even then, I'm surprised there's no optical > drive result at all in the first page of google search. Definitely > doesn't seem like a common term in US. There is just a lot more "odd" goings-on in the US. Korea is simply less odd than the US :) Will send a patch to fix... Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/power/opp.txt b/Documentation/power/opp.txt index 3035d00..4a17443 100644 --- a/Documentation/power/opp.txt +++ b/Documentation/power/opp.txt @@ -1,5 +1,5 @@ *=============* -* OPP Library * +* Operating Performance Points (OPP) Library * *=============* (C) 2009-2010 Nishanth Menon <nm@ti.com>, Texas Instruments Incorporated @@ -16,6 +16,8 @@ Contents 1. Introduction =============== +1.1 What is an Operating Performance Point (OPP)? + Complex SoCs of today consists of a multiple sub-modules working in conjunction. In an operational system executing varied use cases, not all modules in the SoC need to function at their highest performing frequency all the time. To @@ -25,6 +27,16 @@ more. The set of discrete tuples consisting of frequency and voltage pairs that the device will support per domain are called Operating Performance Points or OPPs. +As an example: +MPU device supports {300MHz at minimum voltage of 1V}, {800MHz at minimum +voltage of 1.2V}, {1GHz at minimum voltage of 1.3V} +We can represent these as three OPPs +{300000, 1000000} +{800000, 1200000} +{1000000, 1300000} + +1.2 Operating Performance Points Library + OPP library provides a set of helper functions to organize and query the OPP information. The library is located in drivers/base/power/opp.c and the header is located in include/linux/opp.h. OPP library can be enabled by enabling