netdev - Re: [PATCH net-next 0/4] bnxt_en: Add new "enable_hot_fw

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Date:   Tue, 19 May 2020 11:41:32 +0200
From:   Jiri Pirko <jiri@...nulli.us>
To:     Michael Chan <michael.chan@...adcom.com>
Cc:     Vasundhara Volam <vasundhara-v.volam@...adcom.com>,
        David Miller <davem@...emloft.net>,
        Netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next 0/4] bnxt_en: Add new "enable_hot_fw_reset"
 generic devlink parameter

Tue, May 19, 2020 at 10:41:44AM CEST, michael.chan@...adcom.com wrote:
>On Tue, May 19, 2020 at 12:30 AM Jiri Pirko <jiri@...nulli.us> wrote:
>>
>> Tue, May 19, 2020 at 07:43:01AM CEST, vasundhara-v.volam@...adcom.com wrote:
>> >On Tue, May 19, 2020 at 10:57 AM Jiri Pirko <jiri@...nulli.us> wrote:
>> >>
>> >> I don't follow, sorry. Could you be more verbose about what you are
>> >> trying to achieve here?
>> >As mentioned below, hot_fw_reset is a device capability similar to roce.
>> >Capability can be enabled or disabled on the device, if the device supports.
>> >When enabled and if supported firmware and driver are loaded, user can
>> >utilise the capability to fw_reset or fw_live_patch.
>>
>> I don't undestand what exactly is this supposed to enable/disable. Could
>> you be more specific?
>
>Let me see if I can help clarify.  Here's a little background.  Hot
>reset is a feature supported by the firmware and requires the
>coordinated support of all function drivers.  The firmware will only
>initiate this hot reset when all function drivers can support it.  For
>example, if one function is running a really old driver that doesn't
>support it, the firmware will not support this until this old driver
>gets unloaded or upgraded.  Until then, a PCI reset is needed to reset
>the firmware.
>
>Now, let's say one function driver that normally supports this
>firmware hot reset now wants to disable this feature.  For example,
>the function is running a mission critical application and does not
>want any hot firmware reset that may cause a hiccup during this time.
>It will use this devlink parameter to disable it.  When the critical
>app is done, it can then re-enable the parameter.  Of course other
>functions can also disable it and it is only enabled when all
>functions have enabled it.
>
>Hope this clarifies it.  Thanks.

Okay. So this is about the "allowing to be reseted from the outside".
I see. For that I think it makes sense to have the devlink param.
However, I think that it would be fine to find more suitable name and
describe this properly in the docs.