Re: [PATCH] mmc_spi: do propper retry managment in the block layer

[Pierre Ossman]

On Wed, 8 Apr 2009 10:55:53 +0100
Wolfgang MÃes <wolfgang.mues@xxxxxxxxxxxx> wrote:

> From: Wolfgang Muees <wolfgang.mues@xxxxxxxxxxxx>
> 
> o This patch adds a propper retry managment for reading
>   and writing data blocks for mmc and mmc_spi. Blocks are
>   retransmitted 2 times in case of a transmission failure.
>   This patch was tested with induced transmission errors
>   by ESD pulses (and survived).
> 
> Signed-off-by: Wolfgang Muees <wolfgang.mues@xxxxxxxxxxxx>
> 

NAK. Writes cannot be retried safely as upper layers rely on the fact
that writes fail in a linear manner (a stupid assumption IMO, but
that's the way things are).

> +		/* Invalid response. This is most likely a transmission
> +		 * error from card to host.
> +		 */
> +		case -EINVAL:

EINVAL is actually "host controller driver/hardware does not support
this type of request".

Rgds
-- 
     -- Pierre Ossman

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