Re: [PATCH] mmc_spi: fail gracefully if host or card do not supportthe switch command

From: Pierre Ossman
Date: Sat Jun 13 2009 - 07:08:48 EST


On Thu, 11 Jun 2009 16:13:27 +0100
Wolfgang MÃes <wolfgang.mues@xxxxxxxxxxxx> wrote:

> From: Wolfgang Muees <wolfgang.mues@xxxxxxxxxxxx>
>
> The switch command (typically speed switching from 25 to 50 MHz clock)
> can be rejected by _both_ the host controller/driver and by the card.
> Elder revisions of the SD card do not support speed switching.
> Fail gracefully if the reject is comming from the card.
>
> Signed-off-by: Wolfgang Muees <wolfgang.mues@xxxxxxxxxxxx>
>

Have you ever seen this in practice? For SD there are several checks
before the switch command is actually issued. Sounds like there is
something else wrong here. Have you turned off your EMP thingy? ;)

PS. Please use the @ossman.eu address.

Rgds
--
-- Pierre Ossman

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