linux-kernel - Re: [PATCH] net/cadence/macb: clear interrupts simply and correctly

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Date:	Wed, 18 Jun 2014 17:44:31 +0900
From:	Jongsung Kim <neidhard.kim@....com>
To:	Nicolas Ferre <nicolas.ferre@...el.com>,
	Sören Brinkmann 
	<soren.brinkmann@...inx.com>
CC:	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>,
	Hayun Hwang <hwang.hayun@....com>,
	Youngkyu Choi <youngkyu7.choi@....com>,
	Cyrille Pitchen <cyrille.pitchen@...el.com>
Subject: Re: [PATCH] net/cadence/macb: clear interrupts simply and correctly

On 06/17/2014 04:54 PM, Nicolas Ferre wrote:

Hi Nicolas,

> On 17/06/2014 05:39, Jongsung Kim :
>> On 06/17/2014 06:28 AM, Sören Brinkmann wrote:
>>> Shouldn't it be sufficient to replace 'MACB_BIT(RCOMP) with 'MACB_RX_INT_FLAGS'
>>> to clear all the RX IRQ flags.
>>
>> I'm afraid not.
>>
>> You know, this driver initially targeted only GEMs configured with "gem_irq_clear_read."
>> For this implementation of GEM, the ISR is automatically cleared by reading. The driver
>> was designed to operate with the value read from ISR, not with the ISR itself.
>>
>> However, there are other GEMs configured without "gem_irq_clear_read," people like you
>> and I working with. To support them, they insert similar codes conditionally clearing
>> the ISR here and there. Now they are found at 6 places. Not enough yet. Do you want to
>> insert another at the end of macb_reset_hw..? Maybe not.
> 
> Can't we separate a bit more the implementations of "clear on read" and
> "clear on write" so that we do not spread the tests that you are talking
> about all over the place and slower the driver's hot paths?

I see. I'll revise my patch. Thank you for your advice.

Regards,
Jongsung
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