Date: Fri, 17 Dec 2010 14:32:27 -0800
From: Greg KH <gregkh@suse.de>
To: Robert Morell <rmorell@nvidia.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>,
        Benoit Goby <benoit@android.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        Sarah Sharp <sarah.a.sharp@linux.intel.com>,
        Matthew Wilcox <willy@linux.intel.com>,
        Ming Lei <tom.leiming@gmail.com>, Jacob Pan <jacob.jun.pan@intel.com>,
        Olof Johansson <olof@lixom.net>, Erik Gilling <konkers@android.com>,
        Colin Cross <ccross@android.com>, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC] Align tegra-ehci DMA transfers to 32B
Message-ID: <20101217223227.GA19418@suse.de>
References: <1292623129-26361-1-git-send-email-rmorell@nvidia.com>
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On Fri, Dec 17, 2010 at 01:58:47PM -0800, Robert Morell wrote:
> This small set of patches fixes an issue where DMA from the tegra EHCI
> controller could be corrupted.  It was most commonly seen with USB network
> adapters, though in theory it could happen with any USB traffic.
> 
> (Note: An attempt was made to fix this with commit 367c3aab, which set
> NET_IP_ALIGN to 0 and NET_SKB_PAD to 32.  Unfortunately, not all network
> drivers honor them (presumably since these are intended as optimizations rather
> than hard rules).  This does mean that properly-written network drivers should
> fall through this code with very little overhead, however.)

We don't have many USB network drivers, why not just fix them up to
handle this properly, then you will not need to change any core USB
code, right?

thanks,

greg k-h
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