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From: Andrew Lunn <andrew@lunn.ch>
To: Claudiu Manoil <claudiu.manoil@nxp.com>
Cc: Zefir Kurtisi <zefir.kurtisi@neratec.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"claudiu.manoil@freescale.com" <claudiu.manoil@freescale.com>
Subject: Re: [PATCH] gianfar: prevent fragmentation in DSA environments
Date: Fri, 19 Aug 2016 18:39:44 +0200	[thread overview]
Message-ID: <20160819163944.GF22939@lunn.ch> (raw)
In-Reply-To: <AM5PR0401MB2561CB4CA30BC13EBFFAD43796160@AM5PR0401MB2561.eurprd04.prod.outlook.com>

> >> -#define GFAR_RXB_SIZE 1536
> >> +/* prevent fragmenation by HW in DSA environments */
> >> +#define GFAR_RXB_SIZE (1536 + RXBUF_ALIGNMENT)
> >
> >Hi Zefir
> >
> >Using RXBUF_ALIGNMENT suggests this has something to do with
> >alignment, not extra headers.
> >
> >How about
> >
> >/* Prevent fragmenation by HW when using extra headers like DSA */
> >#define GFAR_RXB_SIZE (1536 + 8)
> >
> 
> MRBL (Maximum receive buffer length) must be multiple of 64.
> Please consult de hardware documentation at least before prosing
> changes to the driver.
 
Hi Claudiu

Thanks for pointing this out. This makes RXBUF_ALIGNMENT even worse
for understabability, since you say multiples of 64 is important, not
alignment.

How about

/* Prevent fragmentation by HW when using extra headers like DSA,
while respecting the multiple of 64 requirement. */

#define GFAR_RXB_SIZE roundup(1536 + 8, 64)

	Andrew

  reply	other threads:[~2016-08-19 17:24 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-19  9:16 [PATCH] gianfar: prevent fragmentation in DSA environments Zefir Kurtisi
2016-08-19 14:59 ` Andrew Lunn
2016-08-19 15:49   ` Claudiu Manoil
2016-08-19 16:39     ` Andrew Lunn [this message]
2016-08-19 21:24       ` Claudiu Manoil
2016-08-19 21:45         ` Andrew Lunn
2016-08-22 13:44           ` Zefir Kurtisi
2016-08-19 16:43   ` Zefir Kurtisi
2016-08-19 17:05     ` Andrew Lunn

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