From: Jeff Garzik <jgarzik@pobox.com>
To: Greg KH <greg@kroah.com>, Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
akpm@osdl.org, bjorn.helgaas@hp.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@suse.de>
Subject: Re: [PATCH] missing pci_disable_device()
Date: Thu, 09 Sep 2004 15:38:34 -0400 [thread overview]
Message-ID: <4140B13A.3010104@pobox.com> (raw)
In-Reply-To: <20040909173349.GA14633@kroah.com>
Well, the kexec folks have a bit of a point (but not IMO a strong one).
Overall to be friendly with firmware and multi-driver situations we
should try and _restore_ the state of the PCI device prior to
pci_enable_device(), when pci_disable_device() is called.
Some situations -- namely BIOS/ACPI/SMM and kexec -- really do care
about the state of the hardware at shutdown time. Other situations are
purely Linux problems, like what Jens ran into a month or more ago:
* IDE driver loads, including on legacy addresses
* modprobe ata_piix
* pci_enable_device() on a running device
* notice, according to pci_request_regions, that regions are busy
* pci_disable_device()
* IDE suddenly stops working because we disabled IO/MEM
However, with regards to bus-mastering bit specifically, it is
considered a Real Good Idea on a lot of the hardware I mess with to
disable busmastering when you shut down the hardware.
Jeff
next prev parent reply other threads:[~2004-09-09 19:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-07 1:26 [PATCH] missing pci_disable_device() Kenji Kaneshige
2004-09-07 9:49 ` Alan Cox
2004-09-08 3:14 ` Kenji Kaneshige
2004-09-08 12:39 ` Alan Cox
2004-09-09 5:55 ` Kenji Kaneshige
2004-09-09 6:20 ` Greg KH
2004-09-09 10:29 ` Kenji Kaneshige
2004-09-09 13:11 ` Alan Cox
2004-09-10 7:58 ` Kenji Kaneshige
2004-09-09 17:33 ` Greg KH
2004-09-09 19:38 ` Jeff Garzik [this message]
2004-09-10 8:18 ` Kenji Kaneshige
2004-09-13 3:55 ` Kenji Kaneshige
2004-09-14 20:47 ` Greg KH
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