From: rmorell@nvidia.com
To: Greg KH <gregkh@suse.de>
Cc: Oliver Neukum <oliver@neukum.org>,
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-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes
Date: Fri, 17 Dec 2010 15:50:50 -0800 [thread overview]
Message-ID: <20101217235050.GK25105@morell.nvidia.com> (raw)
In-Reply-To: <20101217233527.GA31162@suse.de>
On Fri, Dec 17, 2010 at 03:35:27PM -0800, Greg KH wrote:
> On Sat, Dec 18, 2010 at 12:17:40AM +0100, Oliver Neukum wrote:
> > Am Samstag, 18. Dezember 2010, 00:09:40 schrieb Greg KH:
> > > I still don't like it, it feels like a hack that is not going to be able
> > > to be maintained very well.
> > >
> > > And I still think the individual drivers should be fixed...
> > >
> >
> > But they are not buggy. The USB API was written under the
> > assumption that HCDs can deal with byte level granularity and alignment.
> > Hence the network driver pass DMA-able memory with an alignment
> > that suits them.
>
> Ok, fair enough.
>
> But I still don't like that urb flag stuff as a solution to this...
Yeah, I wish I knew of a better way to store this information.
urb->hcpriv seems like a nice place for host controller-private data,
but it's used by the general ehci framework throughout the lifetime of
an URB so isn't suitable for this case.
Thanks,
Robert
> thanks,
>
> greg k-h
>
next prev parent reply other threads:[~2010-12-17 23:53 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-17 21:58 [RFC] Align tegra-ehci DMA transfers to 32B Robert Morell
2010-12-17 21:58 ` [PATCH 1/2] USB: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2010-12-17 21:58 ` [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2010-12-17 22:35 ` Greg KH
2010-12-17 22:42 ` rmorell
2010-12-17 23:09 ` Greg KH
2010-12-17 23:17 ` Oliver Neukum
2010-12-17 23:35 ` Greg KH
2010-12-17 23:50 ` rmorell [this message]
2010-12-17 23:40 ` rmorell
2010-12-18 0:37 ` Greg KH
2010-12-18 1:29 ` rmorell
2010-12-17 22:32 ` [RFC] Align tegra-ehci DMA transfers to 32B Greg KH
2010-12-17 22:44 ` rmorell
2010-12-17 23:07 ` Greg KH
2010-12-17 23:07 ` David Brownell
2010-12-18 1:49 ` [PATCH v2] " Robert Morell
2010-12-19 21:38 ` [PATCH] " Robert Morell
2011-01-06 23:20 ` [PATCH v4] " Robert Morell
2011-01-20 21:41 ` [PATCH v5] " Robert Morell
2011-01-27 3:06 ` [PATCH v6] " Robert Morell
2011-01-27 3:06 ` [PATCH 1/3] USB: HCD: Add usb_hcd prefix to exported functions Robert Morell
2011-01-27 16:01 ` Alan Stern
2011-01-27 3:06 ` [PATCH 2/3] USB: HCD: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2011-01-27 16:01 ` Alan Stern
2011-01-27 3:06 ` [PATCH 3/3] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2011-02-04 19:49 ` Greg KH
[not found] ` <20110204194954.GA25180-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2011-02-04 20:14 ` Olof Johansson
2011-02-04 20:14 ` Olof Johansson
[not found] ` <AANLkTinRtch4Pvr3GLz5wZU2xkG3FMJxxzSNAdParA7j-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-02-04 20:16 ` Greg KH
2011-02-04 20:16 ` Greg KH
[not found] ` <20110204201616.GA12482-l3A5Bk7waGM@public.gmane.org>
2011-02-04 20:26 ` rmorell-DDmLM1+adcrQT0dZR+AlfA
2011-02-04 20:26 ` rmorell
[not found] ` <20110204202640.GC1744-f3YH7lVHJt/FT5IIyIEb6QC/G2K4zDHf@public.gmane.org>
2011-02-04 20:35 ` Greg KH
2011-02-04 20:35 ` Greg KH
2011-01-20 21:41 ` [PATCH 1/2] USB: HCD: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2011-01-23 3:46 ` Greg KH
2011-01-24 16:32 ` Alan Stern
2011-01-20 21:41 ` [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2011-01-24 16:36 ` Alan Stern
2011-01-24 22:53 ` rmorell
2011-01-25 2:59 ` Alan Stern
2011-01-06 23:20 ` [PATCH v4 1/2] USB: HCD: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2011-01-06 23:20 ` [PATCH v4 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2010-12-19 21:38 ` [PATCH 1/2] USB: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2010-12-19 21:38 ` [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2010-12-19 21:57 ` Oliver Neukum
2010-12-18 1:49 ` [PATCH v2 1/2] USB: Add driver hooks for (un)?map_urb_for_dma Robert Morell
2010-12-18 17:51 ` Greg KH
2010-12-18 1:49 ` [PATCH v2 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes Robert Morell
2010-12-18 17:52 ` Greg KH
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