Announcing OLPC OS 13.2.8 with Sugar 0.110

James Cameron quozl at
Wed Dec 14 16:40:40 EST 2016

On Wed, Dec 14, 2016 at 01:20:54PM -0800, Alex Perez wrote:
> Thanks for the release. It is much appreciated. So far, I’ve flashed
> it just fine on several production XO-1’s I have, both on the
> internal NAND as well as to a 32GB Samsung (Class 6) SD card,
> however in the case of the SD card install, once the flash
> completes, and I’m booted into the 13.2.8 environment , I
> consistently get MMC timeout errors, and the kernel hangs. This is
> easily reproducible by simply running ‘yum update’ from the CLI.
> The exact message emitted by the kernel is “mmc0: Timeout waiting
> for hardware interrupt. mmcblk0: error -110 sending stop command,
> original cmd response 0x900, card status 0xe00.

This is a known symptom on some XO-1 units.  It also varies by SD
card, and is very likely if automatic power management is enabled.  My
build does not enable automatic power management; can you confirm you
did not?

> I can re-boot into the on-board instance of the OS on NAND, and run
> fsck against the filesystem on the SD card, and no filesystem-level
> errors are detected there.
> Do you have any suggestions for follow-up troubleshooting?

It is difficult because SD card is tiny computer with closed-source.

Try shutdown, remove battery, wait ten seconds, restore battery, power
on.  Reason: ensure no CMOS lockup due to ESD.

Try different cards.  Reason: cards vary.

Try different XO-1.  Reason: SD slot circuit varies.

Try read the card fully; e.g. "sudo dd if=/dev/mmcblk0 of=/dev/null".
Reason: card firmware will rewrite any flash blocks that are close to
read disturb threshold count.  As a result timing of future read will
be changed.

Try fs-update on same card in an XO-1.5, XO-1.75, or XO-4, and leave
laptop at ok prompt for a couple of minutes, then move the card to the
XO-1.  Reason: card firmware may not be capable of recovery from
sudden power loss after write; the XO-1 fs-update pauses for only ten
seconds before power donw.

James Cameron

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