linux-kernel - Re: [PATCH 1/1] usb: usleep_range is preferred over udelay where wakeup is flexible

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Message-ID: <20150624142848.GA6226@debianBox.chennai.cdac.in>
Date:	Wed, 24 Jun 2015 19:58:48 +0530
From:	Sunny Kumar <sunny.kumar.roy@...il.com>
To:	mdharm-usb@...-eyed-alien.net, gregkh@...uxfoundation.org,
	linux-usb@...r.kernel.org, usb-storage@...ts.one-eyed-alien.net,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] usb: usleep_range is preferred over udelay where
 wakeup is flexible

Ok so what about putting lower limit to 125 and increase upper limit 200


Sunny

On Wed, Jun 24, 2015 at 12:24:29PM +0530, Sunny Kumar wrote:
> According to Documentation/timers/timers-howto.txt"
> udelay() is only called once from a place where sleeping is allowed.
> We can replace it with a call to usleep_range()
> with a reasonable upper limit.
> 
> Signed-off-by: Sunny Kumar <sunny.kumar.roy@...il.com>
> ---
>  drivers/usb/storage/transport.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
> index 540add2..7cd45ac 100644
> --- a/drivers/usb/storage/transport.c
> +++ b/drivers/usb/storage/transport.c
> @@ -1111,7 +1111,7 @@ int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
>  	 * command phase and the data phase.  Some devices need a little
>  	 * more than that, probably because of clock rate inaccuracies. */
>  	if (unlikely(us->fflags & US_FL_GO_SLOW))
> -		udelay(125);
> +		usleep_range(100, 125);
>  
>  	if (transfer_length) {
>  		unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
> -- 
> 2.1.4
> 

View attachment "0001-usb-usleep_range-is-preferred-over-udelay-where-wake.patch" of type "text/x-diff" (1203 bytes)