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Subject: Re: [PATCH] usb: dwc3: gadget: fix miss isoc issue introduced by IRQ
 latency
To:     Zeng Tao <prime.zeng@hisilicon.com>, balbi@kernel.org
Cc:     liangshengjun@hisilicon.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1544805179-2248-1-git-send-email-prime.zeng@hisilicon.com>
From:   Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Organization: Cogent Embedded
Message-ID: <67af347c-39fb-a11c-ab95-7741c58b6dd6@cogentembedded.com>
Date:   Fri, 14 Dec 2018 14:17:47 +0300
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Hello!

On 12/14/2018 07:32 PM, Zeng Tao wrote:

> If it's a busy system, some times when we start an isoc transfer, the
> framenumber get from the event buffer may be already elasped, in this

   Frame number? Else my spell checker trips. :-)

>  case, we will get all the packets dropped due to miss isoc. And we turn

   Remove the leading space, please.

> into transfer nothing, to fix this issue, we need to fix the framenumber
> to make sure that it's not out of date.
> 
> Signed-off-by: Liang Shengjun <liangshengjun@hisilicon.com>
> Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com>
[...]
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 9f92ee0..b63bd72 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1263,6 +1263,15 @@ static int __dwc3_gadget_get_frame(struct dwc3 *dwc)
>  	return DWC3_DSTS_SOFFN(reg);
>  }
>  
> +static bool __dwc3_gadget_target_frame_elapsed(struct dwc3_ep *dep)
> +{
> +	u16 cframe =  __dwc3_gadget_get_frame(dep->dwc);
> +	u16 eframe = dep->frame_number & DWC3_EVENT_PRAM_SOFFN_MASK;
> +
> +	return (((eframe - cframe) & DWC3_EVENT_PRAM_SOFFN_MASK)
> +		> DWC3_EVENT_PRAM_MAX_SOFFN / 2);

   Please leave > on the previous line.
   And you surely know that the outer parens are unnecessary? :-)

[...]

MBR, Sergei