Date: Tue, 25 Nov 2008 00:03:06 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Mel Gorman <mel@csn.ul.ie>
Cc: petkovbb@gmail.com, sshtylyov@ru.mvista.com, linux-kernel@vger.kernel.org
Subject: Re: Is the change to IDE probing really necessary?
Message-ID: <20081125000306.014f7771@lxorguk.ukuu.org.uk>
In-Reply-To: <20081124230948.GB8293@csn.ul.ie>
References: <20081124155632.GE23190@csn.ul.ie>
	<20081124184321.GA8293@csn.ul.ie>
	<20081124185453.57ca7dcc@lxorguk.ukuu.org.uk>
	<20081124230948.GB8293@csn.ul.ie>
Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street,
 Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a
 Lloegr o'r rhif cofrestru 3798903
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1615
Lines: 37

> Then can the message outputted printed out say something along those
> lines? On this particular machine, probing 0x3F resulted in a misconfigured

That is exactly what it says at the moment.

> machine. It's not obvious to me at all that 0x3F means probe everything,
> possibly with adverse results and 0x03 means peer at primary/secondary.

> Which in this case resulted in no disk because the mask defaults to 0
> now instead of 0x3 or anything else.

The mask is set to 0 and then the master/slave are detected based upon
the presence of PCI IDE devices on the master/slave ports.

> What you suggest for the numbers in each case is right, but it's not
> obvious. The machine might be so old that no will encounter this problem
> in practice.

That is why pata_legacy does it automatically. Users shouldn't need to.

> > If you want it to just work automatically use pata_legacy instead as that
> > automatically flips between probing ISA tertiary devices and leaving
> > things well alone according to the presence of PCI bus.
> > 
> 
> It doesn't find the disk.

If pata_legacy fails to find the disk then please send me an lspci
-vvxxx, chances are you shouldn't be using pata_legacy or ide_generic in
the first place but have a PCI device and don't have the right driver
loaded (or we don't have a right driver in which case it needs the
heuristics fixing up)
--
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/