Re: [PATCH] igb: add parameter to ignore nvm checksum validation

From: Florian Fainelli <f.fainelli@gmail.com>
To: Daniel Walker <danielwa@cisco.com>
Cc: "Nikunj Kela (nkela)" <nkela@cisco.com>,
	"jeffrey.t.kirsher@intel.com" <jeffrey.t.kirsher@intel.com>,
	"xe-linux-external(mailer list)" <xe-linux-external@cisco.com>,
	"David S. Miller" <davem@davemloft.net>,
	"intel-wired-lan@lists.osuosl.org"
	<intel-wired-lan@lists.osuosl.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] igb: add parameter to ignore nvm checksum validation
Date: Thu, 16 May 2019 18:48:43 -0700	[thread overview]
Message-ID: <bd9e6a93-c8e8-a90e-25b0-26ccbf65b7c4@gmail.com> (raw)
In-Reply-To: <20190517010330.2wynopuhsqycqzuq@zorba>


On 5/16/2019 6:03 PM, Daniel Walker wrote:
> On Thu, May 16, 2019 at 03:02:18PM -0700, Florian Fainelli wrote:
>> On 5/16/19 12:55 PM, Nikunj Kela (nkela) wrote:
>>>
>>>
>>> On 5/16/19, 12:35 PM, "Jeff Kirsher" <jeffrey.t.kirsher@intel.com> wrote:
>>>
>>>     On Wed, 2019-05-08 at 23:14 +0000, Nikunj Kela wrote:
>>>    >> Some of the broken NICs don't have EEPROM programmed correctly. It
>>>    >> results
>>>    >> in probe to fail. This change adds a module parameter that can be
>>>    >> used to
>>>    >> ignore nvm checksum validation.
>>>    >> 
>>>    >> Cc: xe-linux-external@cisco.com
>>>    >> Signed-off-by: Nikunj Kela <nkela@cisco.com>
>>>    >> ---
>>>    >>  drivers/net/ethernet/intel/igb/igb_main.c | 28
>>>    >> ++++++++++++++++++++++------
>>>    >>  1 file changed, 22 insertions(+), 6 deletions(-)
>>>     
>>>     >NAK for two reasons.  First, module parameters are not desirable
>>>     >because their individual to one driver and a global solution should be
>>>     >found so that all networking device drivers can use the solution.  This
>>>     >will keep the interface to change/setup/modify networking drivers
>>>     >consistent for all drivers.
>>>
>>>     
>>>     >Second and more importantly, if your NIC is broken, fix it.  Do not try
>>>     >and create a software workaround so that you can continue to use a
>>>     >broken NIC.  There are methods/tools available to properly reprogram
>>>     >the EEPROM on a NIC, which is the right solution for your issue.
>>>
>>> I am proposing this as a debug parameter. Obviously, we need to fix EEPROM but this helps us continuing the development while manufacturing fixes NIC.
>>
>> Then why even bother with sending this upstream?
> 
> It seems rather drastic to disable the entire driver because the checksum
> doesn't match. It really should be a warning, even a big warning, to let people
> know something is wrong, but disabling the whole driver doesn't make sense.

You could generate a random Ethernet MAC address if you don't have a
valid one, a lot of drivers do that, and that's a fairly reasonable
behavior. At some point in your product development someone will
certainly verify that the provisioned MAC address matches the network
interface's MAC address.
-- 
Florian