Re: [dpdk-dev] [PATCH] app/testpmd: set fixed flag when exact link speed is chosen

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 4/23/19 6:04 PM, Ferruh Yigit wrote:
> On 4/23/2019 4:02 PM, Ferruh Yigit wrote:
>> On 4/12/2019 2:12 PM, Andrew Rybchenko wrote:
>>> Setting exact link speed makes sense if auto-negotiation is
>>> disabled. Fixed flag is required to disable auto-negotiation.
>> Hi Andrew,
>>
>> Fixed link speed is not supported by all PMDs and this change is breaking them
>> to set the speed in testpmd.

Not all. sfc definitely supports it.
It looks like bnxt, e1000, igb support it as well.

>> As long as device speed set correct, I believe the command doesn't really care
>> about if link mode is auto-negotiation or not.

Sometimes it is really important to disable auto-negotiation.

>> I am for reverting this commit, is there any objection to revert it?
> cc'ing Wenjie who reported the issue.

May be I misunderstood the purpose of the command.
Typically if someone wants to set link speed, it is assumed that
auto-negotiation should be disabled since user specifies what he really 
wants.
Of course, it is still valid request to keep auto-negotiation enabled, but
limit set of advertised speeds (may be keep only one).

So, I'm not happy to revert it completely. There is an option to revert 
to old
behaviour and add optional argument to disable auto-negotiation, but I
can't say that I like it, since it would make sense if the command 
allows more
than one speed to be advertised (to be auto-negotiated). If it is only 
one speed,
the default should be autoneg disabled.

Anyway documentation of the command should be improved.

Andrew.

>>> Fixes: 88fbedcd5e5a ("app/testpmd: move speed and duplex parsing in a function")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
>>> ---
>>>   app/test-pmd/cmdline.c | 12 ++++++------
>>>   1 file changed, 6 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
>>> index 2ab03c111..691d818a6 100644
>>> --- a/app/test-pmd/cmdline.c
>>> +++ b/app/test-pmd/cmdline.c
>>> @@ -1440,17 +1440,17 @@ parse_and_check_speed_duplex(char *speedstr, char *duplexstr, uint32_t *speed)
>>>   			return -1;
>>>   		}
>>>   		if (!strcmp(speedstr, "1000")) {
>>> -			*speed = ETH_LINK_SPEED_1G;
>>> +			*speed = ETH_LINK_SPEED_1G | ETH_LINK_SPEED_FIXED;
>>>   		} else if (!strcmp(speedstr, "10000")) {
>>> -			*speed = ETH_LINK_SPEED_10G;
>>> +			*speed = ETH_LINK_SPEED_10G | ETH_LINK_SPEED_FIXED;
>>>   		} else if (!strcmp(speedstr, "25000")) {
>>> -			*speed = ETH_LINK_SPEED_25G;
>>> +			*speed = ETH_LINK_SPEED_25G | ETH_LINK_SPEED_FIXED;
>>>   		} else if (!strcmp(speedstr, "40000")) {
>>> -			*speed = ETH_LINK_SPEED_40G;
>>> +			*speed = ETH_LINK_SPEED_40G | ETH_LINK_SPEED_FIXED;
>>>   		} else if (!strcmp(speedstr, "50000")) {
>>> -			*speed = ETH_LINK_SPEED_50G;
>>> +			*speed = ETH_LINK_SPEED_50G | ETH_LINK_SPEED_FIXED;
>>>   		} else if (!strcmp(speedstr, "100000")) {
>>> -			*speed = ETH_LINK_SPEED_100G;
>>> +			*speed = ETH_LINK_SPEED_100G | ETH_LINK_SPEED_FIXED;
>>>   		} else if (!strcmp(speedstr, "auto")) {
>>>   			*speed = ETH_LINK_SPEED_AUTONEG;
>>>   		} else {
>>>