i/o read/write errors with SD

Hi,

Which Android release are you using for this test? Can you try with another SD Card with lesser capacity (8GB or less) and see if this problem goes away?

Satheesh.

Hi Satheesh, Thanks for your response

        I am using PandaBoard L27.12.1-P2 release. I even suspected that issue can be 16GB SD, but how should I prove its failing due to 16GB memory card. with 4GB SD cards It is working fine. I want to know the root cause for this behavior. Generally most of android devices provides booting from eMMC and with an internal memory of 16 or 32 GB. How its possible with those devices. Please help me in this regard considering issue with 16GB SD or 16GB eMMC

Thanks.

Hi Vamshi,

Could you please try the following patch? Some of the SD Card require bigger timeout for access. You need to manually merge these changes in your kernel.

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 690255c..0f2caca 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -280,7 +280,11 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
         if (data->flags & MMC_DATA_WRITE)

-            limit_us = 300000;
+            limit_us = 3000000;
         else
-             limit_us = 100000;
+             limit_us = 1000000;

If this does not work, you can try increasing the boot partition size from 64M to 512M and see if this fixes the issue.

Also, in future please post pandaboard related questions to pandaboard@googlegroups.com Strictly speaking this forum is not for pandaboard discussions.

Regards, Satheesh

Hi Sathessh,

        Sorry, In future I will post issues at pandaboard@googlegroups.com

I have tried applying the above specified patch, It did not help me still I have the same Issue.  I booted from SD and entered into fastboot and formated eMMC it is of 16GB size and the partition table I created using fastboot is as follows. (I have made necessary changes in u-boot for partitioning eMMC)

new partition table:

256  128K xloader

512 256K bootloader

2048 8M recovery

18432 8M boot

34816 512M system

1083392 256M cache

1607680 512M userdata

2656256 13615M media

Am I missing any thing while partition eMMC or in filesystem creation. 

the error gave this card status 0x400e00

card status is 32 bit field, With above status I could infer that it is CRC error and card was in programming mode.

Should I change the boot partition from 8M => 64M

Thanks. 

Hi Satheesh,

       I am trying to verify the clock provided to eMMC, as per TRM maximum clock is 48MHZ for eMMC, but omap-hsmmc.c is trying to configure 52MHz. I am trying to cross check this. I will try your suggestions changing the partition size once I am sure about clock.

Thanks.

Hi Sateesh,

        I have a doubt regarding partition sizes. Does the partition size of and img should match the partition size of the disk space on eMMC. 

for example, actual size of system.img is 184MB, and during its creation partition size is specified as 512M which is same as that of 512M partition on eMMC.

Where to set the partition size for recovery image ?

Thanks.

Hi Vamshi,

I am not clear on your question. I am unable to understand why you want to change the system and recovery partition of the eMMC. My understanding was that you have a problem in using a 16GB SD Card. My suggestion was to format the 16GB card as an 8GB card or less to see if the problem goes away. This might give some clue to debug the original problem you were facing.

Satheesh

Hi Vamsi, 

Did you solved this SD card problem? I am getting same error and not able to find whats going on there?

Please share your solution if you solved this. 

Thanks

Yogesh