From: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz,
akpm@osdl.org, greg@kroah.com, ak@suse.de,
rmk+lkml@arm.linux.org.uk
Subject: Re: [PATCH 0/6] PCI legacy I/O port free driver (take2)
Date: Thu, 23 Feb 2006 14:58:51 +0900 [thread overview]
Message-ID: <43FD4F1B.9000307@jp.fujitsu.com> (raw)
In-Reply-To: <1140662098.8264.18.camel@localhost.localdomain>
Benjamin Herrenschmidt wrote:
>>Here, there are many PCI devices that provide both I/O port and MMIO
>>interface, and some of those devices can be handled without using I/O
>>port interface. The reason why such devices provide I/O port interface
>>is for compatibility to legacy OSs. So this kind of devices should
>>work even if enough I/O port resources are not assigned. The "PCI
>>Local Bus Specification Revision 3.0" also mentions about this topic
>>(Please see p.44, "IMPLEMENTATION NOTE"). On the current linux,
>>unfortunately, this kind of devices don't work if I/O port resources
>>are not assigned, because pci_enable_device() for those devices fails.
>
>
> Which is where the real problem is ... I'm afraid you are doing a
> workaround for the wrong issue... do we really need to assign all
> resources to the device at pci_enable_device() time ? Yeah, I know, that
> sounds gross... but think about it... doesn't pci_request_region(s) look
> like a better spot ? Or maybe we should change pci_enable_device()
> itself to take a mask of BARs that are relevant. That would help dealing
> with a couple of other cases of devices where some BARs really need to
> be ignored...
>
> The later is probably the best approach without breaking everything, by
> having a new pci_enable_resources(mask) that would take a mask of BARs
> to enable, with pci_enable_device() becoming just a call to the former
> for all BARs ....
>
> Ben.
>
I guess the existing pci_enable_device_bars() is very similar to
your pci_enable_resources(). We already discussed it at:
http://marc.theaimsgroup.com/?l=linux-kernel&m=114000705026791&w=2
Thanks,
Kenji Kaneshige
prev parent reply other threads:[~2006-02-23 6:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-21 6:26 [PATCH 0/6] PCI legacy I/O port free driver (take2) Kenji Kaneshige
2006-02-21 6:28 ` [PATCH 1/6] PCI legacy I/O port free driver (take2) - Add no_ioport flag into pci_dev Kenji Kaneshige
2006-02-21 21:01 ` Greg KH
2006-02-21 6:29 ` [PATCH 2/6] PCI legacy I/O port free driver (take2) - Fix minor bug in store_new_id() Kenji Kaneshige
2006-02-21 6:30 ` [PATCH 3/6] PCI legacy I/O port free driver (take2) - Add device_flags into pci_device_id Kenji Kaneshige
2006-02-21 13:57 ` Andi Kleen
2006-02-21 20:56 ` Greg KH
2006-02-21 20:59 ` Andi Kleen
2006-02-21 21:10 ` Greg KH
2006-02-21 21:31 ` Andi Kleen
2006-02-21 21:55 ` Jeff Garzik
2006-02-21 22:06 ` Andi Kleen
2006-02-22 0:09 ` Jeff Garzik
2006-02-22 0:11 ` Greg KH
2006-02-22 2:34 ` Kenji Kaneshige
2006-02-23 2:37 ` Benjamin Herrenschmidt
2006-02-23 6:33 ` Kenji Kaneshige
2006-02-21 6:31 ` [PATCH 4/6] PCI legacy I/O port free driver (take2) - Update Documentation/pci.txt Kenji Kaneshige
2006-02-21 6:32 ` [PATCH 5/6] PCI legacy I/O port free driver (take2) - Make Intel e1000 driver legacy I/O port free Kenji Kaneshige
2006-02-21 6:33 ` [PATCH 6/6] PCI legacy I/O port free driver (take2) - Make Emulex lpfc " Kenji Kaneshige
2006-02-21 20:56 ` Greg KH
2006-02-23 2:34 ` [PATCH 0/6] PCI legacy I/O port free driver (take2) Benjamin Herrenschmidt
2006-02-23 5:58 ` Kenji Kaneshige [this message]
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