* Investigating SD card failures
@ 2007-07-27 5:50 Manuel Lauss
2007-07-27 14:30 ` Pierre Ossman
0 siblings, 1 reply; 3+ messages in thread
From: Manuel Lauss @ 2007-07-27 5:50 UTC (permalink / raw)
To: drzeus-mmc; +Cc: linux-kernel
Hi Pierre,
I have a 1GB SanDisk SD card here which linux does not recognize.
Looking at the MMC debug output, I see the MMC core repeatedly
issues CMD55/CMD41 commands (which all succeed!) then stops
after 100 times. In sd_ops.c the code checks for a bit to get set.
My question is, what exactly is this bit supposed to indicate?
Thanks,
Manuel Lauss
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Investigating SD card failures
2007-07-27 5:50 Investigating SD card failures Manuel Lauss
@ 2007-07-27 14:30 ` Pierre Ossman
2007-07-27 16:00 ` Manuel Lauss
0 siblings, 1 reply; 3+ messages in thread
From: Pierre Ossman @ 2007-07-27 14:30 UTC (permalink / raw)
To: Manuel Lauss; +Cc: linux-kernel
On Fri, 27 Jul 2007 07:50:26 +0200
Manuel Lauss <mano@roarinelk.homelinux.net> wrote:
> Hi Pierre,
>
> I have a 1GB SanDisk SD card here which linux does not recognize.
> Looking at the MMC debug output, I see the MMC core repeatedly
> issues CMD55/CMD41 commands (which all succeed!) then stops
> after 100 times. In sd_ops.c the code checks for a bit to get set.
> My question is, what exactly is this bit supposed to indicate?
>
That the card has initialized. Try extending the time that loop runs and see if the card powers up.
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
PulseAudio, core developer http://pulseaudio.org
rdesktop, core developer http://www.rdesktop.org
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Investigating SD card failures
2007-07-27 14:30 ` Pierre Ossman
@ 2007-07-27 16:00 ` Manuel Lauss
0 siblings, 0 replies; 3+ messages in thread
From: Manuel Lauss @ 2007-07-27 16:00 UTC (permalink / raw)
To: Pierre Ossman; +Cc: linux-kernel
Hi Pierre,
Thank your for your answer!
Pierre Ossman wrote:
> On Fri, 27 Jul 2007 07:50:26 +0200
> Manuel Lauss <mano@roarinelk.homelinux.net> wrote:
>
>> Hi Pierre,
>>
>> I have a 1GB SanDisk SD card here which linux does not recognize.
>> Looking at the MMC debug output, I see the MMC core repeatedly
>> issues CMD55/CMD41 commands (which all succeed!) then stops
>> after 100 times. In sd_ops.c the code checks for a bit to get set.
>> My question is, what exactly is this bit supposed to indicate?
>>
>
> That the card has initialized. Try extending the time that loop runs and see if the card powers up.
Did that, waited almost 10 seconds, didn't help. I found a printed
version of the SD spec; it turned out to be a power supply problem.
Apparently the power supply is not strong enough and/or the card
very sensitive to power fluctuations; put in another piece of hardware
with redesigned power supply the card works fine.
Sorry for the noise!
Thanks,
Manuel Lauss
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-07-27 16:01 UTC | newest]
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2007-07-27 5:50 Investigating SD card failures Manuel Lauss
2007-07-27 14:30 ` Pierre Ossman
2007-07-27 16:00 ` Manuel Lauss
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