Re: [PATCH] mmc_spi: use EILSEQ for possible transmission errors

[Pierre Ossman <pierre@ossman.eu>]

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On Wed, 20 May 2009 02:20:46 -0700
David Brownell <david-b@pacbell.net> wrote:

> On Wednesday 20 May 2009, Wolfgang Mües wrote:
> > R1_SPI_COM_CRC is a transmission error - no doubt. Mapping to EILSEQ is OK.
> > 
> > R1_SPI_ERASE_SEQ and R1_SPI_ERASE_RESET are responses to a sector erase 
> > command. block.c is not sending such commands, so block.c can safely assume 
> > that each such response is a transmission error.
> 
> Hmm, would hope that's not a long-term plan.  Remember that the
> firmware in the card can leverage "that's erased" knowledge for
> things like wear leveling.  SSDs and other storage devices would
> likewise benefit from such knowledge.  I'm quite certain there's
> been discussion about adding support for that in the block layer.
> 

It's already in AFAIK. I even had code for hooking it up to mmc_block.
But it didn't produce any measurable results so I never merged it.

Rgds
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     -- Pierre Ossman

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