[dm-crypt] Password is not accepted

ken gebser at mousecar.com
Wed Sep 21 14:57:21 CEST 2011

On 09/20/2011 11:05 PM Milan Broz wrote:
> On 09/21/2011 04:03 AM, Karl O. Pinc wrote:
>> This is all driven by the initramfs.  What happens is that,
>> sometimes, the screen goes black for perhaps 15 or more
>> seconds starting about 3 or 4 seconds after the luks
>> password prompt.  Attempts to enter the password or portion
>> thereof during this time always result in failure.
>> I believe I've seen the same problem without the screen
>> going black as well.  If I wait a long time to enter the
>> password all is well.
> I had problems with late reset of usb devices
> (with connected usb keyboard).
> When I start to enter passphrase (in initramfs), usb kernel
> module resets usb devices (perhaps just initialization)
> and usually it cause lost of some entered characters.
> Waiting few seconds helps - maybe this is the similar case
> or just problem with another hw interfering (like gpu).
> To debug such issues - boot kernel, intramfs (dracut or whatever
> it is) with full debug to console, check what is logged
> immediately before it happens.
> (If it is too quick, just use some camera and record screen
> or log it to serial console.)
> With passphrase entered in late init where things run in
> parallel (like systemd these days) even more magic can happen;-)
> Milan

Is there a way to determine if the USB connection to the encrypted disk 
is good... so that it won't drop any characters in the passphrase? 
E.g., how about running an "fdisk -l" on the drive first, then running 
the "cryptsetup" command?

Better: Is there perhaps an option to cryptsetup (just for testing of 
course) which would make it echo back the passphrase it received...? 
just to ensure that it received what I intended?

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