linux-kernel - Re: [Resend][PATCH] PCI PM: Read device power state from register after updating it

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] [day] [month] [year] [list]

Message-ID: <20091006090855.650ef454@jbarnes-g45>
Date:	Tue, 6 Oct 2009 09:08:55 -0700
From:	Jesse Barnes <jesse.barnes@...el.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Linux PCI <linux-pci@...r.kernel.org>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	Arjan van de Ven <arjan@...radead.org>,
	Andreas Mohr <andi@...as.de>,
	kevin granade <kevin.granade@...il.com>
Subject: Re: [Resend][PATCH] PCI PM: Read device power state from register
 after updating it

On Mon, 5 Oct 2009 00:48:40 +0200
"Rafael J. Wysocki" <rjw@...k.pl> wrote:

> From: Rafael J. Wysocki <rjw@...k.pl>
> 
> After attempting to change the power state of a PCI device
> pci_raw_set_power_state() doesn't check if the value it wrote into
> the device's PCI_PM_CTRL register has been stored in there, but
> unconditionally modifies the device's current_state field to reflect
> the change.  This may cause problems to happen if the power state of
> the device hasn't been changed in fact, because it will make the PCI
> PM core make a wrong assumption.
> 
> To prevent such situations from happening modify
> pci_raw_set_power_state() so that it reads the device's PCI_PM_CTRL
> register after writing into it and uses the value read from the
> register to update the device's current_state field.  Also make it
> print a message saying that the device refused to change its power
> state as requested (returning an error code in such cases would cause
> suspend regressions to appear on some systems, where device drivers'
> suspend routines return error codes if pci_set_power_state() fails).
> 
> Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>

Applied to my for-linus branch, thanks.

-- 
Jesse Barnes, Intel Open Source Technology Center
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/