netdev - Re: [PATCH] net: stmmac: mmc_core: Assign, don't add interrupt registers

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Date: Mon, 19 Feb 2024 12:17:35 -0800
From: Florian Fainelli <f.fainelli@...il.com>
To: Jesper Nilsson <jesper.nilsson@...s.com>
Cc: Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Jose Abreu <joabreu@...opsys.com>, "David S. Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Maxime Coquelin
 <mcoquelin.stm32@...il.com>, netdev@...r.kernel.org,
 linux-stm32@...md-mailman.stormreply.com,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 kernel@...s.com
Subject: Re: [PATCH] net: stmmac: mmc_core: Assign, don't add interrupt
 registers

On 2/19/2024 2:40 AM, Jesper Nilsson wrote:
> On Fri, Feb 16, 2024 at 09:13:51AM -0800, Florian Fainelli wrote:
>> So in premise I agree with the patch, that incrementing those is not the
>> right way to go about them. However these registers are currently provided
>> as part of the statistics set, but they should instead be accessed via the
>> register dumping method.
> 
> You mean extending the dump register code to dump the MAC Management Counter
> registers that are not counters?

Yes that is what I meant.

>  From what I understand it's only the Rx and Tx interrupt and interrupt mask
> registers that aren't counters. Oh, and the MMC control register itself?
> 
> To be honest, I don't think their use can justify the code churn.

Fair enough, it really depends whether they are actually useful in 
troubleshooting or not.

> 
>> In either case you will get at best a snapshot of those two registers at any
>> given time and I suppose this can help diagnose a stuck RX condition, but
>> not much more than that.
> 
> Yeah, their use is very doubtful. For me, they only introduce more nonsense
> data in my logs.
> 
> The Rx registers looks to have been added in the first version of the MMC
> back in 2011, but the Tx registers never was.
> In commit 1c901a46d57 Giuseppe mentions the MMC interrupts as something to
> add later (if actually useful).
> 
> So Serge's suggestion to drop the entries completely is actually quite attractive.

No concerns from me to drop them, not much value in having inaccurate 
information.
-- 
Florian