Re: [PATCH v2 2/2] usb: dwc2: host: Clear interrupts before handling them

From: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>
To: Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	John Youn <John.Youn-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
Cc: "Herrero,
	Gregory"
	<gregory.herrero-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	"Heiko Stübner" <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>,
	"Greg Kroah-Hartman"
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	"linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	"Kaukab,
	Yousaf" <yousaf.kaukab-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	"Yunzhi Li" <lyz-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	"Julius Werner" <jwerner-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	"Dinh Nguyen"
	<dinguyen-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>
Subject: Re: [PATCH v2 2/2] usb: dwc2: host: Clear interrupts before handling them
Date: Thu, 19 Nov 2015 12:19:14 -0600	[thread overview]
Message-ID: <877fldg8d9.fsf@saruman.tx.rr.com> (raw)
In-Reply-To: <CAD=FV=WSypaenJcRjhneAkcW=K5J-q-+c7L2=vJj5YAoGaFncw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

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Hi,

Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> writes:
>>>> isn't this a regression ? You're first clearing the interrupts and only
>>>> then reading to check what's pending, however, what's pending has just
>>>> been cleared. Seems like this should be:
>>>>
>>>> hprt0 = dwc2_readl(HPRT0);
>>>> dwc2_writeal(PRTINT, GINTSTS);
>>>
>>> Actually, we could probably remove the setting of GINTSTS_PRTINT
>>> completely.  The docs I have say that the GINTSTS_PRTINT is read only
>>> and that:
>>>
>>>> The core sets this bit to indicate a change in port status of one of the
>>>> DWC_otg core ports in Host mode. The application must read the
>>>> Host Port Control and Status (HPRT) register to determine the exact
>>>> event that caused this interrupt. The application must clear the
>>>> appropriate status bit in the Host Port Control and Status register to
>>>> clear this bit.
>>>
>>> ...so writing PRTINT is probably useless, but John can confirm.
>>>
>>
>> Yup, it seems it can be removed.
>
> How do you guys want this handled?  Should I send up a new version of
> this patch?  ...or should I send a followon patch that does this
> removal?

I'll leave the final decision to John, but my opinion is that a new
version of the patch would be preferrable.

-- 
balbi

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