Re: [PATCH 3/6] PCI legacy I/O port free driver (take2) - Add device_flags into pci_device_id

From: Jeff Garzik <jgarzik@pobox.com>
To: Andi Kleen <ak@suse.de>
Cc: Greg KH <greg@kroah.com>,
	Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
	linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz,
	akpm@osdl.org, rmk+lkml@arm.linux.org.uk
Subject: Re: [PATCH 3/6] PCI legacy I/O port free driver (take2) - Add device_flags into pci_device_id
Date: Tue, 21 Feb 2006 19:09:08 -0500	[thread overview]
Message-ID: <43FBABA4.7020906@pobox.com> (raw)
In-Reply-To: <200602212306.24342.ak@suse.de>

Andi Kleen wrote:
> On Tuesday 21 February 2006 22:55, Jeff Garzik wrote:
> 
> 
>>It doesn't matter how easily its added, it is the wrong place to add 
>>such things.
>>
>>This is what the various functions called during pci_driver::probe() do...
> 
> 
> The problem is that at least on the e1000 it only applies to some of the 
> many PCI-IDs it supports. So the original patch had an long ugly switch
> with PCI IDs to check it. I suggested to use driver_data for it then,
> but Kenji-San ended up with this new field.  I actually like the idea
> of the new field because it would allow to add such things very easily
> without adding lots of code.
> 
> it's not an uncommon situation. e.g. consider driver A which supports
> a lot of PCI-IDs but MSI only works on a few of them. How do you
> handle this? Add an ugly switch that will bitrot? Or put all the 
> information into a single place which is the pci_device_id array.

You do what tons of other drivers do, and indicate this via driver_data. 
  An enumerated type in driver_data can be used to uniquely identify any 
device or set of devices.

No need to add anything.

	Jeff