From: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
To: David Laight <David.Laight-ZS65k/vG3HxXrIkS9f7CXA@public.gmane.org>
Cc: Sarah Sharp
<sarah.a.sharp-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
Ben Hutchings
<bhutchings-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>,
<netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
<linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: RE: [PATCH] usb: xhci: Link TRB must not occur with a USB payload burst.
Date: Wed, 20 Nov 2013 11:26:52 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1311201121350.1826-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B7438-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
On Wed, 20 Nov 2013, David Laight wrote:
> > From: Sarah Sharp
> ...
> > (Also, usb-storage aligns the block sizes to 512K, which explains why
> > we've never had an issue with TD fragments with that driver.)
>
> What is a 'block' in that context?
I think Sarah means that usb-storage requires the block layer to align
its data buffers to 512-byte boundaries. (Note: 512 bytes, not 512K.)
Disk I/O naturally tends to be done in units of the page size, anyway,
although raw I/O can involve single sectors.
If a user supplies an unaligned buffer, the block layer will set up a
bounce buffer.
Alan Stern
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next prev parent reply other threads:[~2013-11-20 16:26 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-07 17:20 [PATCH] usb: xhci: Link TRB must not occur with a USB payload burst David Laight
2013-11-08 0:18 ` Sarah Sharp
2013-11-08 10:47 ` David Laight
2013-11-08 16:45 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1311081119510.1162-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-11-08 17:39 ` David Laight
2013-11-08 18:12 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1311081303460.1162-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-11-11 17:12 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B73FE-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-11 20:34 ` Alan Stern
2013-11-12 9:43 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B73FF-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-12 16:08 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1311121051090.1200-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-11-12 16:50 ` David Laight
2013-11-12 19:00 ` Alan Stern
2013-11-13 9:28 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B740B-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-13 16:20 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1311131113090.1424-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-11-13 16:58 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B741A-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-16 1:38 ` Ben Hutchings
[not found] ` <1384565904.29151.66.camel-/LGg1Z1CJKQ+9kgCwbf1HqK4ta4zdZpAajtMo4Cw6ucAvxtiuMwx3w@public.gmane.org>
2013-11-18 9:48 ` David Laight
2013-11-18 15:03 ` Ben Hutchings
[not found] ` <1384787003.10077.34.camel-nDn/Rdv9kqW9Jme8/bJn5UCKIB8iOfG2tUK59QYPAWc@public.gmane.org>
2013-11-18 15:41 ` David Laight
2013-11-19 22:58 ` Sarah Sharp
2013-11-20 3:09 ` Alan Stern
2013-11-20 9:36 ` David Laight
2013-11-20 15:03 ` Eric Dumazet
[not found] ` <1384959827.8604.141.camel-XN9IlZ5yJG9HTL0Zs8A6p/gx64E7kk8eUsxypvmhUTTZJqsBc5GL+g@public.gmane.org>
2013-11-20 15:54 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B7437-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-20 16:06 ` Sarah Sharp
2013-11-20 17:02 ` David Laight
2013-11-20 17:16 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B743D-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-20 18:39 ` Sarah Sharp
2013-11-20 21:11 ` Paul Zimmerman
2013-11-21 9:53 ` David Laight
2013-11-20 9:46 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B7438-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-20 16:26 ` Alan Stern [this message]
[not found] ` <Pine.LNX.4.44L0.1311201121350.1826-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-11-20 17:08 ` David Laight
2013-11-20 16:50 ` Sarah Sharp
[not found] ` <Pine.LNX.4.44L0.1311111525480.17105-100000-pYrvlCTfrz9XsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-11-12 17:15 ` Sarah Sharp
2013-11-12 17:33 ` David Laight
2013-11-12 19:22 ` Alan Stern
2013-11-13 9:45 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B740C-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-13 16:27 ` Alan Stern
2013-11-08 11:07 ` David Laight
[not found] ` <AE90C24D6B3A694183C094C60CF0A2F6026B73F1-CgBM+Bx2aUAnGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2013-11-12 17:15 ` Sarah Sharp
2013-11-12 17:28 ` David Laight
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