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

[Brian Hesdorfer <zerophnx@gmail.com>]

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/re58.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