no hotplugging support (FIXME)

no hotplugging support (FIXME)

[Todd and Margo Chester]

Hi Jeff,

I am having a nasty problem with hot swapping a removable (not
eSATA) drive I use for backup on several servers.  It is reported
over on
http://bugs.centos.org/view.php?id=3391

Trying to help me find a work around to the problem at
http://www.centos.org/modules/newbb/viewtopic.php?topic_id=18608&start=0#forumpost68783
Alan posted your ata_piix.c code at
http://centos.toracat.org/ajb/tmp/toddandmargo/ata_piix.c
He pointed out

1483 /* no hotplugging support (FIXME) */
1484 if (!in_module_init)
1485 return -ENODEV;

What do you mean by the comment in line 1483?  Is there some
know issue with hot swapping SATA drives?

Many thanks,
-T

Re: no hotplugging support (FIXME)

[Alan Cox]

> 1483 /* no hotplugging support (FIXME) */
> 1484 if (!in_module_init)
> 1485 return -ENODEV;

The old code does not support PIIX controller hot plug - it does support
drive plugging

Re: no hotplugging support (FIXME)

[Robert Hancock]

Todd and Margo Chester wrote:
> Hi Jeff,
> 
> I am having a nasty problem with hot swapping a removable (not
> eSATA) drive I use for backup on several servers.  It is reported
> over on
> http://bugs.centos.org/view.php?id=3391
> 
> Trying to help me find a work around to the problem at
> http://www.centos.org/modules/newbb/viewtopic.php?topic_id=18608&start=0#forumpost68783 
> 
> Alan posted your ata_piix.c code at
> http://centos.toracat.org/ajb/tmp/toddandmargo/ata_piix.c
> He pointed out
> 
> 1483 /* no hotplugging support (FIXME) */
> 1484 if (!in_module_init)
> 1485 return -ENODEV;
> 
> What do you mean by the comment in line 1483?  Is there some
> know issue with hot swapping SATA drives?

If you're using the ata_piix driver then it means your motherboard is 
not in AHCI mode, so hotplugging is not supported by either the driver 
or controller. You have to enable AHCI for SATA hotplug to work on Intel 
controllers.

Re: no hotplugging support (FIXME)

[Todd and Margo Chester]

Robert Hancock wrote:
> Todd and Margo Chester wrote:
>> Robert Hancock wrote:
>>> Todd and Margo Chester wrote:
>>>> Hi Jeff,
>>>>
>>>> I am having a nasty problem with hot swapping a removable (not
>>>> eSATA) drive I use for backup on several servers.  It is reported
>>>> over on
>>>> http://bugs.centos.org/view.php?id=3391
>>>>
>>>> Trying to help me find a work around to the problem at
>>>> http://www.centos.org/modules/newbb/viewtopic.php?topic_id=18608&start=0#forumpost68783 
>>>>
>>>> Alan posted your ata_piix.c code at
>>>> http://centos.toracat.org/ajb/tmp/toddandmargo/ata_piix.c
>>>> He pointed out
>>>>
>>>> 1483 /* no hotplugging support (FIXME) */
>>>> 1484 if (!in_module_init)
>>>> 1485 return -ENODEV;
>>>>
>>>> What do you mean by the comment in line 1483?  Is there some
>>>> know issue with hot swapping SATA drives?
>>>
>>> If you're using the ata_piix driver then it means your motherboard is 
>>> not in AHCI mode, so hotplugging is not supported by either the 
>>> driver or controller. You have to enable AHCI for SATA hotplug to 
>>> work on Intel controllers.
>>>
>>
>> Hi Robers,
>>
>>    As far as I can tell, ACHI is turned on on my motherboard.
>> I have tried all variation in bios (one of them turns /dev/sdb
>> into /dev/hda).   Does not mean ACHI is working right.
>>
>>    Do you know of any reason why my kernel
>> (CentOS 5.2: 2.6.18-92.1.22.el5) would not support
>> (bugs, etc.) hotplugging?
>>
>>    Also, do you know of a utility that I can use to
>> ask ACHI what is has for me (give me a report)?
>>
>> Many thanks,
>> -T
> 
> If the device is in AHCI mode then the ata_piix driver won't load for it 
> - at least it won't in current kernels, I can't say for sure that it 
> won't in the CentOS 5 version.. You do need to get it using the ahci 
> driver instead of ata_piix or hotplug definitely won't work.
> 
> You can try changing the boot initrd to try to load the AHCI driver 
> instead by changing the scsi_hostadapter entry in /etc/modprobe.conf to 
> be ahci instead of ata_piix, then rebuilding the initrd or reinstalling 
> the kernel RPM. However, if the BIOS isn't set up properly for AHCI mode 
> to work, you'll have to either boot up in rescue mode and fix it, or 
> boot up from a different kernel entry in grub.

Hi Robert,

    Thank you.  I take it there is no probe of the AHCI module.  Rats!

My /etc/modprobe.conf (BIOS: Enhanced SATA Mode):

alias scsi_hostadapter sata_sil
alias eth1 e1000e
alias scsi_hostadapter1 megaraid_mbox
alias scsi_hostadapter2 ata_piix
alias snd-card-0 snd-intel8x0
options snd-card-0 index=0
options snd-intel8x0 index=0
remove snd-intel8x0 { /usr/sbin/alsactl store 0 >/dev/null 2>&1 || : ; 
}; /sbin/modprobe -r --ignore-remove snd-intel8x0

While fooling around with my BIOS, trying to see what happens
in the various SATA modes, the one called "ACHI Compatibility mode"
changed my removable drive from /dev/sdb to /dev/hda.  ("mount /dev/hda"
still hangs for two minutes, then the kernel freezes.)

I am wondering if there is a clue here.  Does the ACHI module load
drives as /dev/sd* or /dev/hd*?

Many thanks,
-T

p.s., just of curiosity, what would the ACHI module look
like in my modprobe.conf?

Re: no hotplugging support (FIXME)

[Robert Hancock]

Todd and Margo Chester wrote:
> Robert Hancock wrote:
>> Todd and Margo Chester wrote:
>>> Robert Hancock wrote:
>>>> Todd and Margo Chester wrote:
>>>>> Hi Jeff,
>>>>>
>>>>> I am having a nasty problem with hot swapping a removable (not
>>>>> eSATA) drive I use for backup on several servers.  It is reported
>>>>> over on
>>>>> http://bugs.centos.org/view.php?id=3391
>>>>>
>>>>> Trying to help me find a work around to the problem at
>>>>> http://www.centos.org/modules/newbb/viewtopic.php?topic_id=18608&start=0#forumpost68783 
>>>>>
>>>>> Alan posted your ata_piix.c code at
>>>>> http://centos.toracat.org/ajb/tmp/toddandmargo/ata_piix.c
>>>>> He pointed out
>>>>>
>>>>> 1483 /* no hotplugging support (FIXME) */
>>>>> 1484 if (!in_module_init)
>>>>> 1485 return -ENODEV;
>>>>>
>>>>> What do you mean by the comment in line 1483?  Is there some
>>>>> know issue with hot swapping SATA drives?
>>>>
>>>> If you're using the ata_piix driver then it means your motherboard 
>>>> is not in AHCI mode, so hotplugging is not supported by either the 
>>>> driver or controller. You have to enable AHCI for SATA hotplug to 
>>>> work on Intel controllers.
>>>>
>>>
>>> Hi Robers,
>>>
>>>    As far as I can tell, ACHI is turned on on my motherboard.
>>> I have tried all variation in bios (one of them turns /dev/sdb
>>> into /dev/hda).   Does not mean ACHI is working right.
>>>
>>>    Do you know of any reason why my kernel
>>> (CentOS 5.2: 2.6.18-92.1.22.el5) would not support
>>> (bugs, etc.) hotplugging?
>>>
>>>    Also, do you know of a utility that I can use to
>>> ask ACHI what is has for me (give me a report)?
>>>
>>> Many thanks,
>>> -T
>>
>> If the device is in AHCI mode then the ata_piix driver won't load for 
>> it - at least it won't in current kernels, I can't say for sure that 
>> it won't in the CentOS 5 version.. You do need to get it using the 
>> ahci driver instead of ata_piix or hotplug definitely won't work.
>>
>> You can try changing the boot initrd to try to load the AHCI driver 
>> instead by changing the scsi_hostadapter entry in /etc/modprobe.conf 
>> to be ahci instead of ata_piix, then rebuilding the initrd or 
>> reinstalling the kernel RPM. However, if the BIOS isn't set up 
>> properly for AHCI mode to work, you'll have to either boot up in 
>> rescue mode and fix it, or boot up from a different kernel entry in grub.
> 
> Hi Robert,
> 
>    Thank you.  I take it there is no probe of the AHCI module.  Rats!
> 
> My /etc/modprobe.conf (BIOS: Enhanced SATA Mode):
> 
> alias scsi_hostadapter sata_sil
> alias eth1 e1000e
> alias scsi_hostadapter1 megaraid_mbox
> alias scsi_hostadapter2 ata_piix
> alias snd-card-0 snd-intel8x0
> options snd-card-0 index=0
> options snd-intel8x0 index=0
> remove snd-intel8x0 { /usr/sbin/alsactl store 0 >/dev/null 2>&1 || : ; 
> }; /sbin/modprobe -r --ignore-remove snd-intel8x0

In CentOS 5 this file mainly gets set up by the installer. If you change 
your BIOS settings you'd have to change it manually and rebuild the 
initrd for the changes to take effect.

> 
> While fooling around with my BIOS, trying to see what happens
> in the various SATA modes, the one called "ACHI Compatibility mode"
> changed my removable drive from /dev/sdb to /dev/hda.  ("mount /dev/hda"
> still hangs for two minutes, then the kernel freezes.)

Yeah, compatbility mode likely isn't what you want. It likely sets up 
the controller for IDE mode.

Motherboard makers are sometimes pretty bad about labelling the settings 
properly. Often AHCI is labelled as RAID mode or something.

> 
> I am wondering if there is a clue here.  Does the ACHI module load
> drives as /dev/sd* or /dev/hd*?

It will be sd*

> 
> Many thanks,
> -T
> 
> p.s., just of curiosity, what would the ACHI module look
> like in my modprobe.conf?

You would change:

alias scsi_hostadapter2 ata_piix

to

alias scsi_hostadapter2 ahci

Re: no hotplugging support (FIXME)

[Todd and Margo Chester]

Robert Hancock wrote:
>> p.s., just of curiosity, what would the ACHI module look
>> like in my modprobe.conf?
> 
> You would change:
> 
> alias scsi_hostadapter2 ata_piix
> 
> to
> 
> alias scsi_hostadapter2 ahci
> 
Thank you!

Question: would that be in addition to or a substitute
for?  (I am concerned that my SATA DVD/CD burner would
stop working.)

Also, I downloaded the recent manual for my motherboard.
The section has a new option not on my BIOS (1.2a)
called "SATA ACHI Mode: on|off".  The current BIOS is
2.1a -- I think it is time I ordered a new BIOS chip
(I don't flash.  I remove and replace the chip.  That way
I can go back if things go wrong, which has happened to
me before.)

Many thanks,
-T

Re: no hotplugging support (FIXME)

[Robert Hancock]

Todd and Margo Chester wrote:
> Robert Hancock wrote:
>>> p.s., just of curiosity, what would the ACHI module look
>>> like in my modprobe.conf?
>>
>> You would change:
>>
>> alias scsi_hostadapter2 ata_piix
>>
>> to
>>
>> alias scsi_hostadapter2 ahci
>>
> Thank you!
> 
> Question: would that be in addition to or a substitute
> for?  (I am concerned that my SATA DVD/CD burner would
> stop working.)

Normally all the ports are AHCI if it's switched into that mode, so it 
shouldn't be an issue. However, you could leave in ata_piix as the third 
entry, so that the system will still boot if it's not in AHCI mode 
properly. There's no real harm in having unnecessary drivers in there..

> 
> Also, I downloaded the recent manual for my motherboard.
> The section has a new option not on my BIOS (1.2a)
> called "SATA ACHI Mode: on|off".  The current BIOS is
> 2.1a -- I think it is time I ordered a new BIOS chip
> (I don't flash.  I remove and replace the chip.  That way
> I can go back if things go wrong, which has happened to
> me before.)
> 
> Many thanks,
> -T

Re: no hotplugging support (FIXME)

[Todd and Margo Chester]

Robert Hancock wrote:

> Normally all the ports are AHCI if it's switched into that mode, so it 
> shouldn't be an issue. However, you could leave in ata_piix as the third 
> entry, so that the system will still boot if it's not in AHCI mode 
> properly. There's no real harm in having unnecessary drivers in there..

Sorry for the thousand questions.  Thank you for being so gracious.

Question: once I boot up, is there a way to tell which drive
is using which driver?

Many thanks,
-T

Re: no hotplugging support (FIXME)

[Robert Hancock]

Todd and Margo Chester wrote:
> Robert Hancock wrote:
> 
>> Normally all the ports are AHCI if it's switched into that mode, so it 
>> shouldn't be an issue. However, you could leave in ata_piix as the 
>> third entry, so that the system will still boot if it's not in AHCI 
>> mode properly. There's no real harm in having unnecessary drivers in 
>> there..
> 
> Sorry for the thousand questions.  Thank you for being so gracious.
> 
> Question: once I boot up, is there a way to tell which drive
> is using which driver?

You should be able to tell from the bootup dmesg output which driver 
ends up detecting the ports..

Re: no hotplugging support (FIXME)

[Todd and Margo Chester]

Robert Hancock wrote:
> Todd and Margo Chester wrote:
>> Robert Hancock wrote:
>>>> p.s., just of curiosity, what would the ACHI module look
>>>> like in my modprobe.conf?
>>>
>>> You would change:
>>>
>>> alias scsi_hostadapter2 ata_piix
>>>
>>> to
>>>
>>> alias scsi_hostadapter2 ahci
>>>
>> Thank you!
>>
>> Question: would that be in addition to or a substitute
>> for?  (I am concerned that my SATA DVD/CD burner would
>> stop working.)
> 
> Normally all the ports are AHCI if it's switched into that mode, so it 
> shouldn't be an issue. However, you could leave in ata_piix as the third 
> entry, so that the system will still boot if it's not in AHCI mode 
> properly. There's no real harm in having unnecessary drivers in there..

Once I get the achi module all loaded up correctly, would
I be able to get away with

alias scsi_hostadapter2 ahci
alias scsi_hostadapter3 ata_piix

in my /etc/modprobe.conf?

Re: no hotplugging support (FIXME)

[Todd and Margo Chester]

Robert Hancock wrote:
> Todd and Margo Chester wrote:
>> Robert Hancock wrote:
>>> Todd and Margo Chester wrote:
>>>> Hi Jeff,
>>>>
>>>> I am having a nasty problem with hot swapping a removable (not
>>>> eSATA) drive I use for backup on several servers.  It is reported
>>>> over on
>>>> http://bugs.centos.org/view.php?id=3391
>>>>
>>>> Trying to help me find a work around to the problem at
>>>> http://www.centos.org/modules/newbb/viewtopic.php?topic_id=18608&start=0#forumpost68783 
>>>>
>>>> Alan posted your ata_piix.c code at
>>>> http://centos.toracat.org/ajb/tmp/toddandmargo/ata_piix.c
>>>> He pointed out
>>>>
>>>> 1483 /* no hotplugging support (FIXME) */
>>>> 1484 if (!in_module_init)
>>>> 1485 return -ENODEV;
>>>>
>>>> What do you mean by the comment in line 1483?  Is there some
>>>> know issue with hot swapping SATA drives?
>>>
>>> If you're using the ata_piix driver then it means your motherboard is 
>>> not in AHCI mode, so hotplugging is not supported by either the 
>>> driver or controller. You have to enable AHCI for SATA hotplug to 
>>> work on Intel controllers.
>>>
>>
>> Hi Robers,
>>
>>    As far as I can tell, ACHI is turned on on my motherboard.
>> I have tried all variation in bios (one of them turns /dev/sdb
>> into /dev/hda).   Does not mean ACHI is working right.
>>
>>    Do you know of any reason why my kernel
>> (CentOS 5.2: 2.6.18-92.1.22.el5) would not support
>> (bugs, etc.) hotplugging?
>>
>>    Also, do you know of a utility that I can use to
>> ask ACHI what is has for me (give me a report)?
>>
>> Many thanks,
>> -T
> 
> If the device is in AHCI mode then the ata_piix driver won't load for it 
> - at least it won't in current kernels, I can't say for sure that it 
> won't in the CentOS 5 version.. You do need to get it using the ahci 
> driver instead of ata_piix or hotplug definitely won't work.
> 
> You can try changing the boot initrd to try to load the AHCI driver 
> instead by changing the scsi_hostadapter entry in /etc/modprobe.conf to 
> be ahci instead of ata_piix, then rebuilding the initrd or reinstalling 
> the kernel RPM. However, if the BIOS isn't set up properly for AHCI mode 
> to work, you'll have to either boot up in rescue mode and fix it, or 
> boot up from a different kernel entry in grub.
> 

Hi Robert,

I have

$ modprobe --dry-run -v ahci
insmod /lib/modules/2.6.18-92.1.22.el5/kernel/drivers/ata/ahci.ko

in my system.  Do I just use "modprobe" to install the module
and go edit /etc/modprobe.conf?

And, does the modprobe insertion stay permanent (survives a reboot)?

I am confused   :-[   Can you point me to a link that gives the
directions?

-T

Re: no hotplugging support (FIXME)

[Robert Hancock]

Todd and Margo Chester wrote:
> Robert Hancock wrote:
>> Todd and Margo Chester wrote:
>>> Robert Hancock wrote:
>>>> Todd and Margo Chester wrote:
>>>>> Hi Jeff,
>>>>>
>>>>> I am having a nasty problem with hot swapping a removable (not
>>>>> eSATA) drive I use for backup on several servers.  It is reported
>>>>> over on
>>>>> http://bugs.centos.org/view.php?id=3391
>>>>>
>>>>> Trying to help me find a work around to the problem at
>>>>> http://www.centos.org/modules/newbb/viewtopic.php?topic_id=18608&start=0#forumpost68783 
>>>>>
>>>>> Alan posted your ata_piix.c code at
>>>>> http://centos.toracat.org/ajb/tmp/toddandmargo/ata_piix.c
>>>>> He pointed out
>>>>>
>>>>> 1483 /* no hotplugging support (FIXME) */
>>>>> 1484 if (!in_module_init)
>>>>> 1485 return -ENODEV;
>>>>>
>>>>> What do you mean by the comment in line 1483?  Is there some
>>>>> know issue with hot swapping SATA drives?
>>>>
>>>> If you're using the ata_piix driver then it means your motherboard 
>>>> is not in AHCI mode, so hotplugging is not supported by either the 
>>>> driver or controller. You have to enable AHCI for SATA hotplug to 
>>>> work on Intel controllers.
>>>>
>>>
>>> Hi Robers,
>>>
>>>    As far as I can tell, ACHI is turned on on my motherboard.
>>> I have tried all variation in bios (one of them turns /dev/sdb
>>> into /dev/hda).   Does not mean ACHI is working right.
>>>
>>>    Do you know of any reason why my kernel
>>> (CentOS 5.2: 2.6.18-92.1.22.el5) would not support
>>> (bugs, etc.) hotplugging?
>>>
>>>    Also, do you know of a utility that I can use to
>>> ask ACHI what is has for me (give me a report)?
>>>
>>> Many thanks,
>>> -T
>>
>> If the device is in AHCI mode then the ata_piix driver won't load for 
>> it - at least it won't in current kernels, I can't say for sure that 
>> it won't in the CentOS 5 version.. You do need to get it using the 
>> ahci driver instead of ata_piix or hotplug definitely won't work.
>>
>> You can try changing the boot initrd to try to load the AHCI driver 
>> instead by changing the scsi_hostadapter entry in /etc/modprobe.conf 
>> to be ahci instead of ata_piix, then rebuilding the initrd or 
>> reinstalling the kernel RPM. However, if the BIOS isn't set up 
>> properly for AHCI mode to work, you'll have to either boot up in 
>> rescue mode and fix it, or boot up from a different kernel entry in grub.
>>
> 
> Hi Robert,
> 
> I have
> 
> $ modprobe --dry-run -v ahci
> insmod /lib/modules/2.6.18-92.1.22.el5/kernel/drivers/ata/ahci.ko
> 
> in my system.  Do I just use "modprobe" to install the module
> and go edit /etc/modprobe.conf?
> 
> And, does the modprobe insertion stay permanent (survives a reboot)?

Running modprobe only loads the module for the current session. You have 
to edit /etc/modprobe.conf to get it to be loaded on boot-up. Also, 
since this driver is needed to mount the root filesystem, you have to 
rebuild the initrd afterwards so that it will contain that driver - you 
should be able to do:

mkinird -f /boot/initrd-2.6.18-92.1.22.el5.img 2.6.18-92.1.22.el5

> 
> I am confused   :-[   Can you point me to a link that gives the
> directions?
> 
> -T