From: Jongsung Kim <neidhard.kim@lge•com>
To: "Sören Brinkmann" <soren.brinkmann@xilinx•com>
Cc: netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
Nicolas Ferre <nicolas.ferre@atmel•com>,
"David S. Miller" <davem@davemloft•net>,
Hayun Hwang <hwang.hayun@lge•com>,
Youngkyu Choi <youngkyu7.choi@lge•com>
Subject: Re: [PATCH] net/cadence/macb: clear interrupts simply and correctly
Date: Tue, 17 Jun 2014 13:42:47 +0900 [thread overview]
Message-ID: <539FC747.3060908@lge.com> (raw)
In-Reply-To: <0f1d404c-89a7-4bbd-99ff-973d4f26d2c6@BY2FFO11FD005.protection.gbl>
On 06/17/2014 12:50 PM, Sören Brinkmann wrote:
> On Tue, 2014-06-17 at 11:38AM +0900, Jongsung Kim wrote:
>> On 06/16/2014 11:56 PM, Sören Brinkmann wrote:
>>> On Mon, 2014-06-16 at 02:00PM +0900, Jongsung Kim wrote:
>>>> On 06/13/2014 12:44 AM, Sören Brinkmann wrote:
>>>>> This is now clearing all IRQ flags which is probably not what we want
>>>>> here. This is handling RX only. We still want the non-RX interrupts to go to
>>>>> the actual interrupt service routing.
>>>>
>>>> The ISR(Interrupt Status Register) is read only in the interrupt service
>>>> routine, macb_interrupt. But is partially cleared here and there. Further
>>>> handler-functions decide jobs to be done by reading/checking other status
>>>> registers. (e.g., TSR, RSR) So, clearing the ISR after reading looks not
>>>> a bad idea.
>>>
>>> But you are clearing _all_ interrupt flags in the RX NAPI handler.
>>> Doesn't that mean we might miss certain events?
>>
>> Please inspect my patch again. What I did in the macb_poll is removing
>> statements clearing the Rx-complete interrupt, not clearing all the
>> interrupts.
>
> Why is clearing those bits removed? It's probably not a big hit, but it might
> result in a pointless interrupt which could be avoided. But it should
> probably clear all RX interrupts - MACB_RX_INT_FLAGS - instead of just RCOMP.
> For clear-on-read implementations it shouldn't make a difference.
I agree. But I removed it because I think stepping the same procedure
regardless of the "gem_irq_clear_read" implementation is better than
implementation-specific optimization.
> And in the if-condition in that new helper, I'd add '&& status' to
> avoid writing back zeros.
Good point. I'll add it when I resend v2.
Jongsung
next prev parent reply other threads:[~2014-06-17 4:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-12 8:50 [PATCH] net/cadence/macb: clear interrupts simply and correctly Jongsung Kim
2014-06-12 15:44 ` Sören Brinkmann
2014-06-16 5:00 ` Jongsung Kim
2014-06-16 14:56 ` Sören Brinkmann
2014-06-17 2:38 ` Jongsung Kim
2014-06-17 3:50 ` Sören Brinkmann
2014-06-17 4:42 ` Jongsung Kim [this message]
2014-06-16 21:28 ` Sören Brinkmann
2014-06-17 3:39 ` Jongsung Kim
2014-06-17 7:54 ` Nicolas Ferre
2014-06-18 8:44 ` Jongsung Kim
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