Re: PXA27x SD/MMC card CRC errors - only sometimes

On Sat, 2005-12-17 at 13:12 -0700, Matthew Mastracci wrote:
> I've been banging my head against a problem with the PXA SD/MMC driver 
> for a couple of days and I thought I'd fish for any suggestions here on 
> what might be going on.
> 
> I have the driver working on the Palm Treo 650 for *most* SD cards, but 
> certain cards cause it to get back invalid CRC data whenever it attempts 
> to read from the card.  Since it works in some cases, I guess it's just 
> some quirk of the card itself that isn't handled in the driver.
> 
> I tried clocking it down below 19.5MHz (to avoid the PXA27x errata that 
> indicates that some cards might be a problem at that speed), but that 
> didn't seem to have any effect.
> 
> I figured I'd fish for anything here before I start building up a test 
> program from scratch to figure out what might be failing.  Any ideas?

I have no answer but there are other people seeing issues. There was
mention of this on linus-arm-kernel:

http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-December/032798.html

In the followup, I suggested trying lowering the clock speed which
helped but didn't cure the problem.

It looks like there are some bugs somewhere, perhaps in the timeout
handling of the pxa driver although there may be more than one issue
here.

Richard