Re: Sandisk extreme 32GB and 16GB dont initialize in XO-1.75

2012-10-18 Thread John Watlington

Based on that error message, my guess is that those Sandisk cards are the
first to support +1.8V operation.   The kernel is detecting this, but getting
confused as it doesn't know how to turn on +1.8V power to the SD (it isn't
supported by that motherboard).

On XO-1.5, we supported operating SD cards at +1.8V, but since we never
encountered such a card the feature was dropped in XO-1.75/XO-4.   All cards
have to support operation at the +3.3V these systems provide.

The kernel should recognize this limitation, and not try to negotiate for
lower voltages.   This sounds like a bug in build 21, please file a ticket.

Thanks,
wad

On Oct 7, 2012, at 7:33 AM, George Hunt wrote:

 Hi all,
 
 I've been working on a XO-1.75 as XS project. The smallest form factor XS 
 would use an SD card for School Server storage. So I purchased fast, large SD 
 cards from Amazon.  These cards work in my mac, and they initialize, and 
 appear to work on the XO-1.5 running build 860.
 
 The XO-1.75 software is build 21 (12.1.0), firmware is Q4D17.
  
 The error message in the /var/log/messages is:
 Oct  7 11:18:44 schoolserver kernel: [157819.81] sdhci: Switching to 1.8V 
 signalling voltage failed, retrying with S18R set to 0
 Oct  7 11:18:44 schoolserver kernel: [157819.876896] mmc0: error -110 whilst 
 initialising SD card
 
 In my reading about SD cards, I discover that some SD cards are not genuine. 
 I have looked at /sys/... and the manufacturing number was 003 which is 
 appropriate for sandisk.
 
 This error message is mentioned in 
 Ticket #11736
 
 
 I'd be happy to give more info, or do testing. 
 
 George
 
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Re: Sandisk extreme 32GB and 16GB dont initialize in XO-1.75

2012-10-18 Thread Chris Ball
Hi,

On Thu, Oct 18 2012, John Watlington wrote:
 The kernel should recognize this limitation, and not try to negotiate for
 lower voltages.   This sounds like a bug in build 21, please file a ticket.

I just pushed a change to arm-3.0-wip that might fix this -- George,
please can you test?

Thanks,

- Chris.
-- 
Chris Ball   c...@laptop.org   http://printf.net/
One Laptop Per Child
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Re: Sandisk extreme 32GB and 16GB dont initialize in XO-1.75

2012-10-18 Thread George Hunt
All my XO-1.75's are prepped for the SF summit this weekend. I can do it
after Sunday.

George

On Thu, Oct 18, 2012 at 3:22 PM, Chris Ball c...@laptop.org wrote:

 Hi,

 On Thu, Oct 18 2012, John Watlington wrote:
  The kernel should recognize this limitation, and not try to negotiate for
  lower voltages.   This sounds like a bug in build 21, please file a
 ticket.

 I just pushed a change to arm-3.0-wip that might fix this -- George,
 please can you test?

 Thanks,

 - Chris.
 --
 Chris Ball   c...@laptop.org   http://printf.net/
 One Laptop Per Child

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Sandisk extreme 32GB and 16GB dont initialize in XO-1.75

2012-10-07 Thread George Hunt
Hi all,

I've been working on a XO-1.75 as XS project. The smallest form factor XS
would use an SD card for School Server storage. So I purchased fast, large
SD cards from Amazon.  These cards work in my mac, and they initialize, and
appear to work on the XO-1.5 running build 860.

The XO-1.75 software is build 21 (12.1.0), firmware is Q4D17.

The error message in the /var/log/messages is:
Oct  7 11:18:44 schoolserver kernel: [157819.81] sdhci: Switching to
1.8V signalling voltage failed, retrying with S18R set to 0
Oct  7 11:18:44 schoolserver kernel: [157819.876896] mmc0: error -110
whilst initialising SD card

In my reading about SD cards, I discover that some SD cards are not
genuine. I have looked at /sys/... and the manufacturing number was 003
which is appropriate for sandisk.

This error message is mentioned in
Ticket #11736

I'd be happy to give more info, or do testing.

George
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