[dpdk-dev] [PATCH v2 1/2] Added ETH_SPEED_CAP bitmap in rte_eth_dev_info
Marc Sune
marc.sune at bisdn.de
Thu Jun 18 17:06:44 CEST 2015
On 18/06/15 16:43, Morten Brørup wrote:
> Regarding the PHY speed ABI:
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> 1. The Ethernet PHY ABI for speed, duplex, etc. should be common throughout the entire DPDK. It might be confusing if some structures/functions use a bitmask to indicate PHY speed/duplex/personality/etc. and other structures/functions use a combination of an unsigned integer, duplex flag, personality enumeration etc. (By personality enumeration, I am referring to PHYs with multiple electrical interfaces. E.g. a dual personality PHY might have both an RJ45 copper interface and an SFP module interface, whereof only one can be active at any time.)
Thomas was sending a similar comment and I agreed to do a unified speed
bitmap for both capabilities and link negotiation/link info (v3, waiting
for 2.2 merge window):
http://dpdk.org/ml/archives/dev/2015-June/019207.html
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> 2. The auto-negotiation standard allows the PHY to announce (to its link partner) any subset of its capabilities to its link partner. E.g. a standard 10/100/100 Ethernet PHY (which can handle both 10 and 100 Mbit/s in both half and full duplex and 1 Gbit/s full duplex) can be configured to announce 10 Mbit/s half duplex and 100 Mbit/s full duplex capabilities to its link partner. (Of course, more useful combinations are normally announced, but the purpose of the example is to show that any combination is possible.)
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> The ABI for auto-negotiation should include options to select the list of capabilities to announce to the link partner. The Linux PHY ABI only allows forcing a selected speed and duplex (thereby disabling auto-negotiation) or enabling auto-negotiation (thereby announcing all possible speeds and duplex combinations the PHY is capable of). Don't make the same mistake in DPDK.
I see what you mean, and you are probably right. In any case this is for
a separate patch, if we think it is a necessary feature to implement.
Nevertheless, this makes me rethink about the proposal from Thomas about
unifying _100_HD/_100_FD to 100M, because you will need this
granularity, eventually. @Thomas: opinions?
Thanks
Marc
p.s. Please configure your email client to reply using "In-Reply-To:" to
allow clients and ML archives to use threading.
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> PS: While working for Vitesse Semiconductors (an Ethernet chip company) a long time ago, I actually wrote the API for their line of Ethernet PHYs. So I have hands on experience in this area.
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> Med venlig hilsen / kind regards
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> Morten Brørup
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