Message-ID: <3C987200.4020505@evision-ventures.com>
Date: Wed, 20 Mar 2002 12:26:56 +0100
From: Martin Dalecki <dalecki@evision-ventures.com>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.9) Gecko/20020311
MIME-Version: 1.0
To: Andre Hedrick <andre@linux-ide.org>
CC: Dan Hopper <ku4nf@austin.rr.com>, linux-kernel@vger.kernel.org
Subject: Re: Promise 20265 IDE chip gets detected in wrong order 2.4.x
In-Reply-To: <Pine.LNX.4.10.10203200243010.525-100000@master.linux-ide.org>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org

Andre Hedrick wrote:
> Hi Martin,
> 
> You kind of missed a few points and issues, so I would like to offer you
> some help.

I don't think so. It is the order on the devices on the PCI bus
which matters for the detection order, since linux is just going
over the devices in the same order they are reported by the BIOS supplied
PCI tables, which are most propably manipulated by the on board BIOS-es
of the Fake-RAID controllers.

> This is easily address by applying the exclusive rule of the seeking the
> SouthBridge device.  Once this is found, one generally assumes this to be
> the PCI_BASE_CLASS_BRIDGE + PCI_CLASS_BRIDGE_ISA or 601h.  It will
> (should future unknown) have  a function number of 0 "zero".  Once the
> location of the SB has been determined one seeks for function 1 "one".
> Once SB + func 1 is found, tests for device class PCI_BASE_CLASS_STORAGE +
> PCI_CLASS_STORAGE_IDE or 101h.

Yes this would actually make sense. However nowadays
I would rather love to encourage everybody to just use partition
labels for mount point discrimination instead of plain device
names:

Look for example:

LABEL=/                 /                       ext3    defaults        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2

Becouse there are some other occasions where the kernel will have
to iterate over PCI devices (suspend/resume comes to mind) and where
a different iteration order on behalf of the IDE subsystem may/could
introduce subtile missinteractions.

Dan using disk labels would be the most convenient solutions to
your problem anyway ;-).

However if I think about it again - I'm not at all sure whatever
the root device can be recognized by a label? If not - the grock
partitions code has to be extendid accordingly!

> Unless otherwise specifed this shall always be the INT13 device; however,
> one does not exclude SCSI/RAID or any other device class having rights to
> INT13 hooks.  Since linux does not support these type of BIOS services the
> fore mentioned is the preferred ruleset.
> 
> This would have been applied to 2.5 but you are now free to do so
> yourself.  As for all other booting devices under INT19 calls to load
> option roms, which in the past have been considered valid, permit
> ATA-HBA's to gain access to the priviledge hwgroup pair ide0/ide1.
> 
> This is all a design of detection ordering to override the nasty tricks
> played by chipset venders attempting to do have their secondary host or
> hba to be the preferred hardware to use.
> 
> The history of this problem is a result of HBA's coming to market before
> system chipset.  Also people who have very good and useful systems who
> want to boost their storage performance tend to drift to the HBA world.
> Others who load the system up with every toy in the market place run out
> of interrupts early (past w/ ISA physical slots), they find it useful and
> practical to disable the legacy host to gain back an additional interrupt
> but not loose the total storage device count before the addition of the
> HBA.
> 
> Cheers,
> 
> Andre Hedrick
> LAD Storage Consulting Group
> 
> On Wed, 20 Mar 2002, Martin Dalecki wrote:
> 
> 
>>Dan Hopper wrote:
>>
>>>Andre Hedrick <andre@linux-ide.org> remarked:
>>>
>>>
>>>>append="ide=reverse"
>>>
>>>
>>>You're right, this works, too, and is a lot easier to remember than
>>>the override I used before.  
>>>
>>>
>>>
>>>>Various Mainboard manufacturers do things to place the FAKE-RAID in front
>>>>of the the legacy south bridge.  This is classic Windows spoofing.
>>>>
>>>>
>>>>
>>>>>PDC20265: IDE controller on PCI bus 00 dev 68
>>>>>VP_IDE: IDE controller on PCI bus 00 dev 89
>>>>
>>>So, the I/O port assignments don't in fact properly determine the
>>>assignment order?  I'm gathering from what you're saying that the
>>>current behavior is related to PCI bus location?
>>
>>Precisely: The PCI bus detection order matters.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/