linux-kernel - Re: [PATCH 3/3] PCI Hotplug: workaround for Thunderbolt on Intel DZ77RE-75K motherboard

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20121213204953.GA25085@otc-wbsnb-06>
Date:	Thu, 13 Dec 2012 22:49:53 +0200
From:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Yinghai Lu <yinghai@...nel.org>,
	Greg KH <gregkh@...uxfoundation.org>,
	Miles J Penner <miles.j.penner@...el.com>,
	John Ronciak <john.ronciak@...el.com>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Tushar N Dave <tushar.n.dave@...el.com>,
	"Kirill A. Shutemov" <kirill@...temov.name>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Amos Kong <kongjianjun@...il.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] PCI Hotplug: workaround for Thunderbolt on Intel
 DZ77RE-75K motherboard

On Thu, Dec 13, 2012 at 12:30:04PM -0800, Linus Torvalds wrote:
> On Thu, Dec 13, 2012 at 12:25 PM, Yinghai Lu <yinghai@...nel.org> wrote:
> >
> > Linus will not be happy with those kind of delay.
> 
> Indeed. And the DMI check is bogus too, since the "there can be
> delays" is apparently part of the pcie hotplug spec.

It's ACPI PCI hotplug, not PCIe native hotplug. PCIe hotplug spec is not
relevant.

IIUC, in ACPI case devices should be ready to be enumerated, before you
get notification. Rafael, is it correct?

> So do the sane thing. Retry a few times, with increasingly long delays
> (ie something like start with 10ms, then double the delay until you
> hit 1s, and then just give up: end result, ~2s total wait, but 10ms
> for any sane device that doesn't suck).

PCI rescan is expensive and generate noise in dmesg. We'll end up with
tons of useless messages.

-- 
 Kirill A. Shutemov

Download attachment "signature.asc" of type "application/pgp-signature" (837 bytes)