[gentoo-user] Re: Allow delay for booting from USB device?

[Jonathan Callen <jcallen@gentoo.org>]

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On 04/18/2014 01:49 PM, Brian Hesdorfer wrote:
> On 4/18/2014 1:38 PM, Joost Roeleveld wrote:
>> On Friday 18 April 2014 10:01:35 Brian Hesdorfer wrote:
>>> On 4/18/2014 9:05 AM, Joost Roeleveld wrote:
>>>> On Friday 18 April 2014 12:02:01 Thomas Mueller wrote:
>>>>> Is there a way to make Gentoo or other Linux allow extra time when root is on a USB
>>>>> device?  Any way to say "just a second" or more like 15 seconds before aborting with
>>>>> the message that root partition does not exist?
>>>>> 
>>>>> In this case it's an IDE hard drive in a USB enclosure.
>>>>> 
>>>>> FreeBSD seems to handle this situation better.  I would get a mountroot> prompt, to
>>>>> which I would respond ufs:/dev/ada0p3 and be good.
>>>>> 
>>>>> I could avoid this situation with /boot/loader.conf
>>>>> 
>>>>> legal.realtek.license_ack=1 rsu-rtl8712fw_load="YES" kern.cam.scsi_delay="13000"     #
>>>>> Delay (in ms) before probing SCSI kern.cam.boot_delay="16000"    # Delay (in ms) of
>>>>> root mount for CAM bus hint.re.0.disabled="1"
>>>>> 
>>>>> but don't know if Linux has anything like this.
>>>>> 
>>>>> Only lines 3 and 4 are relevant to this issue; other lines are for different issues.
>>>>> 
>>>>> Tom
>>>> Try adding " rootdelay = 15 "  to the kernel commandline. This should make the kernel
>>>> wait 15 seconds before trying to access the root- device.
>>>> 
>>>> See: http://www.linuxtopia.org/online_books/linux_kernel/kernel_configuration/r e58.html
>>>> 
>>>> I used this myself in the past when booting from USB-devices.
>>>> 
>>>> Kind regards,
>>>> 
>>>> Joost
>>> Tiny Core linux, which is primarily booted over usb, does something similar. If I'm
>>> understanding this right, they have a loop in their initrd that just waits a maximum of X
>>> seconds until it shows up.
>>> 
>>> I'm not sure how easy this would be to move into something else.
>>> 
>>> Lines 114-128: 
>>> http://git.tinycorelinux.net/index.cgi?url=Core-scripts.git/tree/etc/init.d/ tc-config
>> " rootdelay " is a standard linux kernel option. No need to use a special script.
>> 
>> -- Joost
> 
> Agreed! Hadn't heard of that option until you mentioned it. Learn a new thing everyday :)
> 
> 

There is also a "rootwait" option, which simply waits until the root device is available, no
matter how long that takes. (So you don't end up waiting longer than required "just in case").

- -- 
Jonathan Callen
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