linux-kernel - Re: [PATCH 2/2] USB: ehci-platform: Support ehci reset after resume quirk

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: <Pine.LNX.4.44L0.1412221101540.23710-100000@netrider.rowland.org>
Date:	Mon, 22 Dec 2014 11:06:20 -0500 (EST)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Wu Liang feng <wulf@...k-chips.com>
cc:	heiko@...ech.de, <huangtao@...k-chips.com>,
	<kever.yang@...k-chips.com>, <eddie.cai@...k-chips.com>,
	<roy.li@...k-chips.com>, <zyw@...k-chips.com>,
	<jwerner@...gle.com>, <dianders@...gle.com>, <posciak@...gle.com>,
	<tfiga@...gle.com>, <linux-kernel@...r.kernel.org>,
	<linux-usb@...r.kernel.org>
Subject: Re: [PATCH 2/2] USB: ehci-platform: Support ehci reset after resume
 quirk

On Mon, 22 Dec 2014, Wu Liang feng wrote:

> The EHCI controller doesn't properly detect the case when

"The" EHCI controller?  I don't know what EHCI controller you're 
talking about, but my controllers don't have any trouble detecting 
device removal during suspend.

> a device is removed during suspend. Specifically,when we
> resume from suspend the EHCI controller maintaining the
> USB state (FLAG_CF is 1 Current Connect Status is 1) but
> a USB device (like a USB camera on rk3288) may have been
> disconnected actually.
> 
> Let's add a quirk to force ehci to go into the
> usb_root_hub_lost_power() path and reset after resume.
> This should generally reset the whole controller and all
> ports and initialize everything cleanly again, and bring
> the devices back up.

Isn't this solution too extreme?  What if the device was a flash 
storage drive and it wasn't unplugged during suspend?  This patch would 
force it to be removed, messing up any mounted filesystems, when there 
was no need.

Can you find a better way to work around the problem?

Alan Stern

--
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/