Hi Sowimi,

Thanks for your response. I have a few remarks inline.

On Sep 12, 2008, at 3:12 PM, Sowmini.Varadhan at Sun.COM wrote:

> On (09/12/08 00:55), Joost Mulders wrote:
>>
>> There are 2 sets of properties named MAC_PROP_ADV_ and MAC_PROP_EN_.
>> There is a 3rd set, the defaults, that is implemented as a bit named
>
> Well, the MAC_PROP_DEFAULT flag is not specific to the adv/en  
> versions-
> it applies to all properties, and is a flag asking the driver to
> return the default value for that property. I think that your  
> suggestion
> of adding a parallel set of properties to return default would result
> in propery space bloat.
>
>> MAC_PROP_DEFAULT in pr_flags. It was unclear to me for which  
>> properties
>> defaults are actually retrieved. It might be cleaner to spell out all
>> properties for which defaults are required as MAC_PROP_DEFAULT_.
>
> dladm makes the decision based on whether the default value is
> known globally for all drivers, or if the default
> value depends on the  driver implementation/hardware/link-type
> etc. In the latter case, the driver will be contacted.

Thus drivers must return defaults for all properties.

>
>
> if the concern is that you don't know which ones to implement, then
> you could safely implement return values for all of them that are
> supported.

And thus the bloat? (is that http://en.wikipedia.org/wiki/Bloat) of  
properties in the driver. If dladm spells out exactly for what  
Ethernet properties defaults are required, drivers don't need to  
implement say a default for
say MAC_PROP_ADV_1000FDX_CAP and MAC_PROP_EN_1000FDX_CAP.


>
>> When adv_autoneg_cap is 0, a link's speed and duplex should be  
>> writable
>> properties. Currently, these are readonly, which results in funny
>> implementations. e1000g for example, selects the "best" speed and  
>> duplex
>> from the enabled set (MAC_PROP_EN_*_CAP) when autoneg is turned  
>> off. I
>> found this confusing. IMHO, it would be better to have speed duplex
>> readonly when autoneg is on and writable when autoneg is off.
>
> There was a long discussion around this in the early stages
> of Brussels. See
> http://mail.opensolaris.org/pipermail/brussels-dev/2007-June/000192.html
> My understanding is that speed/duplex can only be strictly set
> as pairs, hence the 10fdx, 10hdx, 100fdx etc. hooks.

I don't understand this requirement. I don's see why speed and duplex  
can be independantly writable when autoeg is off, but I don't think  
it's important to make fuss about it :-)

>
>
>> The -p option for dladm's set-linkprop and show-linkprop doesn't add
>> value for me. Today, dladm's syntax is "dladm command -p prop=val  
>> link".
>> I think it would easier to just have "dladm command prop=val link".
>> Especially because -p is used elsewhere in dladm for producing  
>> parseable
>> output.
>
> I too have frequently forgotten the "-p" in my usage and run into
> this, but Meem's already addressed the motivation for this elsewhere.
>
>> There is a property called adv_autoneg_cap. I think it's cleaner to
>> rename this one to  "autoneg" or "linknegotiation". There's no such
>> thing as an advertised autoneg capability.
>
> adv_autoneg_cap comes directly from the ieee802.3(5) definitions. If
> we are going to rename this, we should be careful not to create
> conflicts with other MII params like cap_autoneg.
>
> --Sowmini
>
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> brussels-dev at opensolaris.org
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-- 
Joost Mulders             +  email: joost.mulders at sun.com
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