netdev - RE: [PATCH v3 1/1] net: fec: ptp: avoid register access when ipg clock is disabled

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Message-ID: <430c40fbef314217a8c2609b9aebbd90@BLUPR03MB373.namprd03.prod.outlook.com>
Date:	Tue, 19 Aug 2014 01:50:53 +0000
From:	"fugang.duan@...escale.com" <fugang.duan@...escale.com>
To:	Richard Cochran <richardcochran@...il.com>
CC:	"davem@...emloft.net" <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"shawn.guo@...aro.org" <shawn.guo@...aro.org>
Subject: RE: [PATCH v3 1/1] net: fec: ptp: avoid register access when ipg
 clock is disabled

From: Richard Cochran <richardcochran@...il.com> Sent: Tuesday, August 19, 2014 3:42 AM
>To: Duan Fugang-B38611
>Cc: davem@...emloft.net; netdev@...r.kernel.org; shawn.guo@...aro.org
>Subject: Re: [PATCH v3 1/1] net: fec: ptp: avoid register access when ipg
>clock is disabled
>
>On Mon, Aug 18, 2014 at 06:07:00AM +0000, fugang.duan@...escale.com wrote:
>> 1. Set the flag to false firstly.
>
>Yes.
>
>> 2. Don't need to add mutex to protect the flag.(My previous mail ask
>> one mutex to protect the flag)
>
>You *do* need a mutex to protect the state of the physical clock. One
>process might turn it off while another process is still reading it.
>
>>    Just pull the flag into the protected field by spin_lock_irqsave()
>like :
>> fec_time_keep()
>
>No, the spin only protects the register access.
>
>Thanks,
>Richard

Ok, I will send the next version with mutex protect the physical clock state.

Thanks,
Andy
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