linux-kernel - Re: [PATCH 2/2] spi/pxa2xx: use a flag to check if the device is runtime suspended

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: <20130618180948.GP1403@sirena.org.uk>
Date:	Tue, 18 Jun 2013 19:09:48 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc:	linux-kernel@...r.kernel.org, Eric Miao <eric.y.miao@...il.com>,
	Russell King <linux@....linux.org.uk>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	Grant Likely <grant.likely@...aro.org>
Subject: Re: [PATCH 2/2] spi/pxa2xx: use a flag to check if the device is
 runtime suspended

On Tue, Jun 18, 2013 at 05:29:45PM +0300, Mika Westerberg wrote:
> Current code calls pm_runtime_suspended() in the interrupt handler to check
> if the device is suspended or not. However, runtime PM status of the device
> is only set to suspended once all PM runtime suspend hooks have executed.

> In our case we have the device bound to the ACPI power domain and its
> runtime suspend hook will put the device to D3hot (or D3cold if possible).
> This effectively means that the device is powered off before its state is
> set to runtime suspended. During this time, it might get an interrupt that
> is meant for another device (as the interrupt line is shared), and because
> the device is powered off accessing its registers will return 0xffffffff
> that the driver misinterprets as an invalid state. When this happens user
> will see messages like below on the console:

This sounds like a problem which will affect a lot of devices and hence
ought to be handled better by the PM core or at least frameworks in
general.  Is it really device specific?

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