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Date:	Tue, 29 Jul 2008 02:21:36 +0400
From:	Sergei Shtylyov <sshtylyov@ru.mvista.com>
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To:	Manuel Lauss <mano@roarinelk.homelinux.net>
Cc:	drzeus@drzeus.cx, linux-mips@linux-mips.org
Subject: Re: [PATCH] au1xmmc: raise segment size limit.
References: <20080728133120.GB26494@roarinelk.homelinux.net>
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Hello.

Manuel Lauss wrote:
> Please apply this patch, as it fixes an oops when MMC-DMA and network
> traffic are active at the same time.  This seems to be a 2.6.27-only thing;
> the current au1xmmc code (minus the polling parts) works fine on 2.6.26.
>
> ---
>
> Raise the DMA block size limit from 2048 bytes to the maximum supported
> by the DMA controllers on the chip (128kB on Au1100, 4MB on Au1200).
>
> This gives a small performance boost and apparently fixes an oops when
> MMC-DMA and network traffic are active at the same time.
>
> Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
>
>   
[...]
> diff --git a/drivers/mmc/host/au1xmmc.c b/drivers/mmc/host/au1xmmc.c
> index 99b2091..dd414f1 100644
> --- a/drivers/mmc/host/au1xmmc.c
> +++ b/drivers/mmc/host/au1xmmc.c
> @@ -61,7 +61,13 @@
>  
>  /* Hardware definitions */
>  #define AU1XMMC_DESCRIPTOR_COUNT 1
> -#define AU1XMMC_DESCRIPTOR_SIZE  2048
> +
> +/* max DMA seg size: 64kB on Au1100, 4MB on Au1200 */
>   

  So, it's 64 or 128 KB? KB since k prefix usualy means decimal kilo... :-)

WBR, Sergei