disabling ata devices

JM jmartin37 at speakeasy.net
Wed Jun 15 14:16:42 GMT 2005

Björn König wrote:

> JM wrote:
>> i'm not exactly sure how to accomplish this... i'm having problems 
>> with my cd-rom, which isn't surprising since it's a slim-line without 
>> UDMA and probably isn't supported... but... it's eating up time when 
>> i'm booting the system.  i've erased the fstab lines for acd0 but 
>> it's still probing the hardware when i boot the machine.
> Please show the point where it takes time. You have a log in 
> /var/run/dmesg.boot
>> how do i completely disable probing for this device at startup? 
> As far as I know this is not possible (I might be mistaken). Either 
> you remove the hardware or the support for this piece of hardware.
>> if possible i'd like to just remove the device node altogether.  
>> every time i remove /dev/acd0 it's just recreated each time i restart.
> devfs provides a kind of virtual file system which will be created in 
> respect of the devices that are known to the kernel. Everytime you 
> unmount devfs all changes that were directly made to /dev are gone.
>> not sure how to permanently remove it without physically removing it 
>> from the system. is there anyway to remove the node without removing 
>> the iso9660 entry from the kernel?
> The 'CD9660' option in the kernel configuration is a file system 
> support and has nothing necessarily to do with support of hardware 
> devices. I guess you mean 'device atapicd'.
> Björn

from dmesg -a:
ad0: 19077MB <ST92011A/3.04> [38760/16/63] at ata0-master UDMA33
acd0: CDROM <CD-224E/1.7A> at ata0-slave UDMA33
Mounting root from ufs:/dev/ad0s1a

when probing acd0 the system waits for about 10-20 seconds.  i'd like to 
leave the kernel alone since i'd rather not compile out cdrom support 
altogether.  i'd simply like to tell FreeBSD to not probe this device at 
boot.  this way there will be no device node associated with it, no 
timeouts, no lag on booting, etc.

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