Re: [EXT] [PATCH 09/15] qed: use new module_firmware_crashed()

Igor Russkikh
2020-05-12T16:24:43Z

>> So I think its not a good place to insert this call.
>> Its hard to find exact good place to insert it in qed.
>
> Is there a way to check if what happened was indeed a fw crash?

Our driver has two firmwares (slowpath and fastpath).
For slowpath firmware the way to understand it crashed is to observe command
response timeout. This is in qed_mcp.c, around "The MFW failed to respond to
command" traceout.

For fastpath this is tricky, think you may leave the above place as the only
place to invoke module_firmware_crashed()

>
>> One more thing is that AFAIU taint flag gets permanent on kernel, but
> for
>> example our device can recover itself from some FW crashes, thus it'd be
>> transparent for user.
>
> Similar things are *supposed* to recoverable with other device, however
> this can also sometimes lead to a situation where devices are not usable
> anymore, and require a full driver unload / load.
>
>> Whats the logical purpose of module_firmware_crashed? Does it mean fatal
>> unrecoverable error on device?
>
> Its just to annotate on the module and kernel that this has happened.
>
> I take it you may agree that, firmware crashing *often* is not good
> design,
> and these issues should be reported to / fixed by vendors. In cases
> where driver bugs are reported it is good to see if a firmware crash has
> happened before, so that during analysis this is ruled out.

Probably, but still I see some misalignment here, in sense that taint is about
the kernel state, not about a hardware state indication.

devlink health could really be a much better candidate for such things.

Regards
Igor