MMC/SD: data CRC errors and unknown SCR version on 2.6.14

MMC/SD: data CRC errors and unknown SCR version on 2.6.14

[Martin B. Andersen]

Hi

I am having some problems with a couple of SD cards which isn't detected 
correctly when inserted, I have seen this with both Sandisk and Kingston 
cards. I am sorry to bring up issues with this old driver version, I 
know there has been done a lot of work after 2.6.14 with the driver.

...but the setup is this: I have backported the mmc driver from kernel 
2.6.14 to 2.6.12 for my own reasons. I wasn't able to use a newer 
version as the driver interface had changed too much to be feasible.

When inserting a faulty card I can see, when debug output is enabled, 
that the communication and output is identical with a working card up 
until the SCR part. Here the driver reports a data CRC error but 
continues, and then it reports an unknown SCR version either 15 or 3, 
but I gather that the array with the SCR contains junk at this point so 
the SCR version is not to be taken seriously. Some times however it is 
able to succesfully detect and register the card, this is mostly seen 
the first time the driver is loaded, afterwards it keeps failing. Has 
anybody seen this behavior before? Is it timing issues or is it caused 
by faulty cards?

best regards
Martin

Re: MMC/SD: data CRC errors and unknown SCR version on 2.6.14

[Martin B. Andersen]

Found the solution. It was a problem on my ARM platform at91rm9200 which 
didn't have internal pullup's enabled on the CMD and DAT0..DAT3.
I found it by comparing the patch for AT91 kernel 2.6.19 on 
http://maxim.org.za/at91_26.html with the driver I had backported.

regards
Martin