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Help with writing to micro SD card

DISCUSSION Larry Finger 2 participants 2 messages May 14, 2015 MMC, SD and SDIO

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I am helping to get wifi and Bluetooth woring under Linux using a Winbook TW100 tablet. The main goal is working quite well; however, I am only able to run using Live media. Whenever I try to load Linux onto either the internal SD card, or one mounted in the external slot, the process stalls with nothing logged.

I know the external card is OK as I can read or write it when it is mounted in my laptop.

When I received the tablet, I used dd to back up the internal card. When I used a block size of 4M in that operation, it also froze; however, the standard block size (512) worked. That suggests that the standard Linux r/w operations on the device are too fast.

What should I do to get some debug information? If my idea is correct, how might I slow down the I/O to the device?

Thanks,

Larry

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When I received the tablet, I used dd to back up the internal card. When I used a block size of 4M in that operation, it also froze; however, the standard block size (512) worked. That suggests that the standard Linux r/w operations on the device are too fast.

Unlikely.

Quoted 1 line

What should I do to get some debug information?

As its Baytrail-T make sure you have

- Current BIOS
- Latest kernel

If it persists try disabling power management on the SD card interface. It may be worth reading through the ASUS T100TA bug reports and workarounds as that is probably the most poked at platform for BYT/T

Alan