libertas sdio on bf548 w/ uclinux

Pierre Ossman drzeus at
Thu Apr 24 08:49:34 EDT 2008

On Tue, 22 Apr 2008 14:28:36 -0400
Dan Williams <dcbw at> wrote:

> On Tue, 2008-04-22 at 13:04 -0500, Nick Moszer wrote:
> > As a follow up to this, here is the libertas debug info right before it 
> > bombs.
> Probably need to get Pierre's input here...  I'm not sure how the SDIO
> stack is supposed to interact with controllers that have certain
> padding/alignment constraints.
> Pierre?

What a delightful mess of top posting...

As for controllers with certain padding/alignment constraints, the
answer is simply tough luck, get some other hardware that isn't broken.
The MMC/SD/SDIO specs have mandated varying transfer sizes since day
one, so hardware that cannot support that doesn't deserve to be called
a MMC/SD/SDIO controller.

The controller shouldn't BUG though as such requests are perfectly
valid. It should fail them with -EINVAL, indicating that the hardware
is unable to satisfy the request.

And yes, the behaviour of the libertas card is consistent with what
I've been seeing. My guess is that it transfers one chunk that tells it
how much data that follows.

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