Re: IBM HDAPS things are looking up

[Jens Axboe <axboe@suse.de>]

On Mon, Jul 04 2005, Lenz Grimmer wrote:
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> Hash: SHA1
> 
> Hi Jens!
> 
> Thanks for the sample code. I've trimmed the recipient list a bit...
> 
> Jens Axboe wrote:
> 
> > Perhaps the IDLE or IDLEIMMEDIATE commands imply a head parking, that
> > would make sense. As you say, you can hear a drive parking its head.
> > Here's a test case, it doesn't sound like it's parking the hard here.
> 
> Not here either, but let me check, if I understand this correctly:
> 
> > #include <stdio.h>
> > #include <unistd.h>
> > #include <fcntl.h>
> > #include <sys/ioctl.h>
> > #include <linux/hdreg.h>
> > 
> > int main(int argc, char *argv[])
> > {
> > 	char cmd[4] = { 0xe1, 0, 0, 0 };
> 
> The "0xe1" in here is what is defined as "WIN_IDLEIMMEDIATE" in hdreg.h,
> correct?

Correct.

> > 	int fd;
> > 
> > 	if (argc < 2) {
> > 		printf("%s <dev>\n", argv[0]);
> > 		return 1;
> > 	}
> > 
> > 	fd = open(argv[1], O_RDONLY);
> 
> Hmm, don't I need to actually have *write* access for sending an ioctl?

No, but you need CAP_SYS_RAWIO capability. So run it as root.

> > 	if (fd == -1) {
> > 		perror("open");
> > 		return 1;
> > 	}
> > 
> > 	if (ioctl(fd, HDIO_DRIVE_CMD, cmd))
> > 		perror("ioctl");
> > 
> > 	close(fd);
> > 	return 0;
> > }
> 
> I will give it another try, after clarifying the above questions - maybe
> there is a command that will perform the desired task. If not, I guess
> we're back at snooping what the Windows driver does here...

I'm not aware of a generally specificed command, it's likely that the
ibm drive has a vendor specific one. Or that one of the idle commands
can be configured to park the drive. Or... I'm not sure you'll find
anything interesting in the windows driver, I would imagine that the
user app is the one issuing the ide command (like the linux equiv would
as well).

-- 
Jens Axboe

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