Why is IOCTL_CDROM_READ_TOC so slow?

[Waldeck Schutzer]

Here is something interesting. When I turn the drive back into a plain 
ide (by removing the ide-scsi option from the kernel options), it speeds 
up considerably. Now it rocks! This makes me wonder what the heck is 
going on with the kernel.

Waldeck

Eric Pouech wrote:

> Waldeck Schutzer wrote:
>
>> Hi Eric,
>>
>> It is very strange indeed, but I just tested it again and I'm 
>> convinced that on my system that call can take a few seconds. I'm 
>> also pretty sure there is no concurrent access to the drive and 
>> automount is not running. I even did this on a failsafe session just 
>> to be sure, but still the same thing. 
>
> maybe you could try it with a simple C program:
> 1/ open fd
> 2/ do the read toc ioctl
> 3/ close
> time the operation 2/
>
> > I wonder there is something wrong with my kernel (2.4.18),
>
>> or worse, with my computer. On the other hand, it works pretty fast 
>> on Windows.
>
> rather strange... I reran on my computer win98 cdplayer, and 
> everything's ok.
> I wonder if the CD ROM driver in Linux is not to blame then
>
> A+