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Subject: Re: [RFC PATCH net-next v2 6/7] net: ravb: Enable SW IRQ Coalescing
 for GbEth
To: Paul Barker <paul.barker.ct@bp.renesas.com>, "David S . Miller"
	<davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Jakub Kicinski
	<kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
CC: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>, Wolfram Sang
	<wsa+renesas@sang-engineering.com>, <netdev@vger.kernel.org>,
	<linux-renesas-soc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20240206091909.3191-1-paul.barker.ct@bp.renesas.com>
 <20240206091909.3191-7-paul.barker.ct@bp.renesas.com>
 <2251fe66-11b7-2f30-c905-7bc1b9a57dab@omp.ru>
 <895bdec7-05d6-4435-8be1-fe8ca716cbcb@bp.renesas.com>
From: Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <7c28bbea-0b3f-ee62-05c8-e6f1bc738b0b@omp.ru>
Date: Mon, 12 Feb 2024 23:40:04 +0300
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On 2/12/24 2:45 PM, Paul Barker wrote:
[...]
>>> diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
>>> index 55a7a08aabef..ca7a66759e35 100644
>>> --- a/drivers/net/ethernet/renesas/ravb.h
>>> +++ b/drivers/net/ethernet/renesas/ravb.h
>>> @@ -1078,6 +1078,7 @@ struct ravb_hw_info {
>>>  	unsigned nc_queues:1;		/* AVB-DMAC has RX and TX NC queues */
>>>  	unsigned magic_pkt:1;		/* E-MAC supports magic packet detection */
>>>  	unsigned half_duplex:1;		/* E-MAC supports half duplex mode */
>>> +	unsigned needs_irq_coalesce:1;	/* Requires SW IRQ Coalescing to achieve best performance */
>>
>>    Is this really a hardware feature?
> 
> It's more like a requirement to get the best out of this hardware and the Linux networking stack.
> 
> I considered checking the compatible string in the probe function but I decided that storing a configuration bit in the HW info struct was cleaner.

   Yes, but you added the new bit under the "hardware features" commet. :-)

>>    Also, s/Requires SW/Needs software/ and s/to achieve best performance//,
>> please...
> 
> Will do.

   The comment is too long, I think. :-)

[...]

> Thanks for the review,
> Paul

MBR, Sergey