<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/usb/host, branch v2.6.35.3</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>USB: EHCI: remove PCI assumption</title>
<updated>2010-08-13T20:30:57+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2010-07-14T15:03:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a6b37a9ed03585d0e1e132d424569003be2abba2'/>
<id>a6b37a9ed03585d0e1e132d424569003be2abba2</id>
<content type='text'>
commit ae68a83bdc1971cb02fefc7a686ba6d077065e71 upstream.

This patch (as1405) fixes a small bug in ehci-hcd's isochronous
scheduler.  Not all EHCI controllers are PCI, and the code shouldn't
assume that they are.  Instead, introduce a special flag for
controllers which need to delay iso scheduling for full-speed devices
beyond the scheduling threshold.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
CC: David Brownell &lt;david-b@pacbell.net&gt;
Acked-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ae68a83bdc1971cb02fefc7a686ba6d077065e71 upstream.

This patch (as1405) fixes a small bug in ehci-hcd's isochronous
scheduler.  Not all EHCI controllers are PCI, and the code shouldn't
assume that they are.  Instead, introduce a special flag for
controllers which need to delay iso scheduling for full-speed devices
beyond the scheduling threshold.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
CC: David Brownell &lt;david-b@pacbell.net&gt;
Acked-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6</title>
<updated>2010-07-26T20:06:39+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2010-07-26T20:06:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=592d32cc4156ee512e55c5bc052fdece215f52b2'/>
<id>592d32cc4156ee512e55c5bc052fdece215f52b2</id>
<content type='text'>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6:
  USB: musb: tusb6010: fix compile error with n8x0_defconfig
  USB: FTDI: Add support for the RT System VX-7 radio programming cable
  USB: add quirk for Broadcom BT dongle
  USB: usb-storage: fix initializations of urb fields
  USB: xhci: Set Mult field in endpoint context correctly.
  USB: sisusbvga: Fix for USB 3.0
  USB: adds Artisman USB dongle to list of quirky devices
  USB: xhci: Set EP0 dequeue ptr after reset of configured device.
  USB: Fix USB3.0 Port Speed Downgrade after port reset
  USB: xHCI: Fix another bug in link TRB activation change.
  USB: option: Add support for AMOI Skypephone S2
  USB: New PIDs for Qualcomm gobi 2000 (qcserial)
  USB: ftdi_sio: support for Signalyzer tools based on FTDI chips
  USB: s3c2410_udc: be aware of connected gadget driver
  USB: Expose vendor-specific ACM channel on Nokia 5230
  USB: Add PID for Sierra 250U to drivers/usb/serial/sierra.c
  USB: option: add support for 1da5:4518
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6:
  USB: musb: tusb6010: fix compile error with n8x0_defconfig
  USB: FTDI: Add support for the RT System VX-7 radio programming cable
  USB: add quirk for Broadcom BT dongle
  USB: usb-storage: fix initializations of urb fields
  USB: xhci: Set Mult field in endpoint context correctly.
  USB: sisusbvga: Fix for USB 3.0
  USB: adds Artisman USB dongle to list of quirky devices
  USB: xhci: Set EP0 dequeue ptr after reset of configured device.
  USB: Fix USB3.0 Port Speed Downgrade after port reset
  USB: xHCI: Fix another bug in link TRB activation change.
  USB: option: Add support for AMOI Skypephone S2
  USB: New PIDs for Qualcomm gobi 2000 (qcserial)
  USB: ftdi_sio: support for Signalyzer tools based on FTDI chips
  USB: s3c2410_udc: be aware of connected gadget driver
  USB: Expose vendor-specific ACM channel on Nokia 5230
  USB: Add PID for Sierra 250U to drivers/usb/serial/sierra.c
  USB: option: add support for 1da5:4518
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: xhci: Set Mult field in endpoint context correctly.</title>
<updated>2010-07-26T19:00:58+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2010-07-10T13:48:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c30c791c946a14a03e87819eced562ed28711961'/>
<id>c30c791c946a14a03e87819eced562ed28711961</id>
<content type='text'>
The bmAttributes field of the SuperSpeed Endpoint Companion Descriptor has
different meanings, depending on the endpoint type.  If the endpoint is
isochronous, the bmAttributes field is the maximum number of packets
within a service interval that this endpoint supports.  If the endpoint is
bulk, it's the number of stream IDs this endpoint supports.

Only set the Mult field of the xHCI endpoint context using the
bmAttributes field if the endpoint is isochronous, and the device is a
SuperSpeed device.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The bmAttributes field of the SuperSpeed Endpoint Companion Descriptor has
different meanings, depending on the endpoint type.  If the endpoint is
isochronous, the bmAttributes field is the maximum number of packets
within a service interval that this endpoint supports.  If the endpoint is
bulk, it's the number of stream IDs this endpoint supports.

Only set the Mult field of the xHCI endpoint context using the
bmAttributes field if the endpoint is isochronous, and the device is a
SuperSpeed device.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: xhci: Set EP0 dequeue ptr after reset of configured device.</title>
<updated>2010-07-26T19:00:58+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2010-07-09T15:08:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2d1ee5904bb51ea33c6a6f4bec6b6a243e2432a8'/>
<id>2d1ee5904bb51ea33c6a6f4bec6b6a243e2432a8</id>
<content type='text'>
When a configured device is reset, the control endpoint's ring is reused.
If control transfers to the device were issued before the device is reset,
the dequeue pointer will be somewhere in the middle of the ring.  If the
device is then issued an address with the set address command, the xHCI
driver must provide a valid input context for control endpoint zero.

The original code would give the hardware the original input context,
which had a dequeue pointer set to the top of the ring.  This would cause
the host to re-execute any control transfers until it reached the ring's
enqueue pointer.  When issuing a set address command for a device that has
just been configured and then reset, use the control endpoint's enqueue
pointer as the hardware's dequeue pointer.

Assumption:  All control transfers will be completed or cancelled before
the set address command is issued to the device.  If there are any
outstanding control transfers, this code will not work.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When a configured device is reset, the control endpoint's ring is reused.
If control transfers to the device were issued before the device is reset,
the dequeue pointer will be somewhere in the middle of the ring.  If the
device is then issued an address with the set address command, the xHCI
driver must provide a valid input context for control endpoint zero.

The original code would give the hardware the original input context,
which had a dequeue pointer set to the top of the ring.  This would cause
the host to re-execute any control transfers until it reached the ring's
enqueue pointer.  When issuing a set address command for a device that has
just been configured and then reset, use the control endpoint's enqueue
pointer as the hardware's dequeue pointer.

Assumption:  All control transfers will be completed or cancelled before
the set address command is issued to the device.  If there are any
outstanding control transfers, this code will not work.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: xHCI: Fix another bug in link TRB activation change.</title>
<updated>2010-07-26T19:00:58+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2010-07-09T15:08:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d1dc908a251c8cd87c1a1ad4f2c4a40cdbd8286c'/>
<id>d1dc908a251c8cd87c1a1ad4f2c4a40cdbd8286c</id>
<content type='text'>
Commit 6c12db90f19727c76990e7f4801c67a148b30111 also seems to have
introduced a bug that is triggered when the command ring is about to wrap.
The inc_enq() function will not have moved the enqueue pointer past the
link TRB.  It is supposed to be moved past the link TRB in prepare_ring(),
which should be called before a TD is enqueued.  However, the
queue_command() function never calls the prepare_ring() function because
prepare_ring() is only supposed to be used for endpoint rings.  That means
the enqueue pointer will not be moved past the link TRB, and will get
overwritten.

The fix is to make queue_command() call prepare_ring() with a fake
endpoint status (set to running).  Then the enqueue pointer will get moved
past the link TRB.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 6c12db90f19727c76990e7f4801c67a148b30111 also seems to have
introduced a bug that is triggered when the command ring is about to wrap.
The inc_enq() function will not have moved the enqueue pointer past the
link TRB.  It is supposed to be moved past the link TRB in prepare_ring(),
which should be called before a TD is enqueued.  However, the
queue_command() function never calls the prepare_ring() function because
prepare_ring() is only supposed to be used for endpoint rings.  That means
the enqueue pointer will not be moved past the link TRB, and will get
overwritten.

The fix is to make queue_command() call prepare_ring() with a fake
endpoint status (set to running).  Then the enqueue pointer will get moved
past the link TRB.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>[ARM] pxa: fix incorrect CONFIG_CPU_PXA27x to CONFIG_PXA27x</title>
<updated>2010-07-15T09:20:23+00:00</updated>
<author>
<name>Eric Miao</name>
<email>eric.y.miao@gmail.com</email>
</author>
<published>2010-07-14T13:17:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=59376cc355ebe1dc89c9daea49010b8b171af404'/>
<id>59376cc355ebe1dc89c9daea49010b8b171af404</id>
<content type='text'>
Reported-by: Christian Dietrich &lt;qy03fugy@stud.informatik.uni-erlangen.de&gt;
Signed-off-by: Eric Miao &lt;eric.y.miao@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Reported-by: Christian Dietrich &lt;qy03fugy@stud.informatik.uni-erlangen.de&gt;
Signed-off-by: Eric Miao &lt;eric.y.miao@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: isp1362-hcd, fix double lock</title>
<updated>2010-06-30T15:16:06+00:00</updated>
<author>
<name>Jiri Slaby</name>
<email>jslaby@suse.cz</email>
</author>
<published>2010-06-21T15:02:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1c815577823951ff082fe1201fdd5efec5e6e8ea'/>
<id>1c815577823951ff082fe1201fdd5efec5e6e8ea</id>
<content type='text'>
Stanse found that isp1362_sw_reset tries to take a isp1362_hcd-&gt;lock,
but it is already held in isp1362_hc_stop. Avoid that by introducing
__isp1362_sw_reset which doesn't take the lock and call it from
isp1362_hc_stop. isp1362_sw_reset is then as simple as lock --
__isp1362_sw_reset -- unlock.

Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: Lothar Wassmann &lt;LW@KARO-electronics.de&gt;
Cc: Michael Hennerich &lt;michael.hennerich@analog.com&gt;
Cc: Bryan Wu &lt;cooloney@kernel.org&gt;
Cc: Mike Frysinger &lt;vapier@gentoo.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Stanse found that isp1362_sw_reset tries to take a isp1362_hcd-&gt;lock,
but it is already held in isp1362_hc_stop. Avoid that by introducing
__isp1362_sw_reset which doesn't take the lock and call it from
isp1362_hc_stop. isp1362_sw_reset is then as simple as lock --
__isp1362_sw_reset -- unlock.

Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
Cc: Lothar Wassmann &lt;LW@KARO-electronics.de&gt;
Cc: Michael Hennerich &lt;michael.hennerich@analog.com&gt;
Cc: Bryan Wu &lt;cooloney@kernel.org&gt;
Cc: Mike Frysinger &lt;vapier@gentoo.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: ehci-mxc: bail out on transceiver problems</title>
<updated>2010-06-30T15:16:06+00:00</updated>
<author>
<name>Wolfram Sang</name>
<email>w.sang@pengutronix.de</email>
</author>
<published>2010-06-15T10:34:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4c9715de52b9b6256bf1e9510917111a47b0c176'/>
<id>4c9715de52b9b6256bf1e9510917111a47b0c176</id>
<content type='text'>
The old code registered the hcd even if there were no transceivers
detected, leading to oopses like this if we try to probe a non-existant
ULPI:

[    2.730000] mxc-ehci mxc-ehci.0: unable to init transceiver
[    2.740000] timeout polling for ULPI device
[    2.740000] timeout polling for ULPI device
[    2.750000] mxc-ehci mxc-ehci.0: unable to enable vbus on transceiver
[    2.750000] mxc-ehci mxc-ehci.0: Freescale On-Chip EHCI Host Controller
[    2.760000] mxc-ehci mxc-ehci.0: new USB bus registered, assigned bus number 2
[    2.770000] Unhandled fault: external abort on non-linefetch (0x808) at 0xc4876184
[    2.770000] Internal error: : 808 [#1] PREEMPT
[    2.770000] last sysfs file:
[    2.770000] Modules linked in:
[    2.770000] CPU: 0    Not tainted  (2.6.33.5 #5)
[    2.770000] PC is at ehci_hub_control+0x4d4/0x8f8
[    2.770000] LR is at ehci_mxc_setup+0xbc/0xdc
[    2.770000] pc : [&lt;c0196dfc&gt;]    lr : [&lt;c019bc8c&gt;]    psr: 00000093
[    2.770000] sp : c3815e40  ip : 00000001  fp : 60000013
[    2.770000] r10: c4876184  r9 : 00000000  r8 : c3814000
[    2.770000] r7 : c391d2cc  r6 : 00000001  r5 : 00000001  r4 : 00000000
[    2.770000] r3 : 80000000  r2 : 00000007  r1 : 80000000  r0 : c4876184
[    2.770000] Flags: nzcv  IRQs off  FIQs on  Mode SVC_32  ISA ARM Segment kernel
[    2.770000] Control: 0005317f  Table: a0004000  DAC: 00000017
[    2.770000] Process swapper (pid: 1, stack limit = 0xc3814270)
...

Signed-off-by: Wolfram Sang &lt;w.sang@pengutronix.de&gt;
Cc: Sascha Hauer &lt;s.hauer@pengutronix.de&gt;
Cc: stable &lt;stable@kernel.org&gt;
Acked-by: Daniel Mack &lt;daniel@caiaq.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The old code registered the hcd even if there were no transceivers
detected, leading to oopses like this if we try to probe a non-existant
ULPI:

[    2.730000] mxc-ehci mxc-ehci.0: unable to init transceiver
[    2.740000] timeout polling for ULPI device
[    2.740000] timeout polling for ULPI device
[    2.750000] mxc-ehci mxc-ehci.0: unable to enable vbus on transceiver
[    2.750000] mxc-ehci mxc-ehci.0: Freescale On-Chip EHCI Host Controller
[    2.760000] mxc-ehci mxc-ehci.0: new USB bus registered, assigned bus number 2
[    2.770000] Unhandled fault: external abort on non-linefetch (0x808) at 0xc4876184
[    2.770000] Internal error: : 808 [#1] PREEMPT
[    2.770000] last sysfs file:
[    2.770000] Modules linked in:
[    2.770000] CPU: 0    Not tainted  (2.6.33.5 #5)
[    2.770000] PC is at ehci_hub_control+0x4d4/0x8f8
[    2.770000] LR is at ehci_mxc_setup+0xbc/0xdc
[    2.770000] pc : [&lt;c0196dfc&gt;]    lr : [&lt;c019bc8c&gt;]    psr: 00000093
[    2.770000] sp : c3815e40  ip : 00000001  fp : 60000013
[    2.770000] r10: c4876184  r9 : 00000000  r8 : c3814000
[    2.770000] r7 : c391d2cc  r6 : 00000001  r5 : 00000001  r4 : 00000000
[    2.770000] r3 : 80000000  r2 : 00000007  r1 : 80000000  r0 : c4876184
[    2.770000] Flags: nzcv  IRQs off  FIQs on  Mode SVC_32  ISA ARM Segment kernel
[    2.770000] Control: 0005317f  Table: a0004000  DAC: 00000017
[    2.770000] Process swapper (pid: 1, stack limit = 0xc3814270)
...

Signed-off-by: Wolfram Sang &lt;w.sang@pengutronix.de&gt;
Cc: Sascha Hauer &lt;s.hauer@pengutronix.de&gt;
Cc: stable &lt;stable@kernel.org&gt;
Acked-by: Daniel Mack &lt;daniel@caiaq.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: r8a66597: Fix failure in change of status</title>
<updated>2010-06-30T15:16:05+00:00</updated>
<author>
<name>Nobuhiro Iwamatsu</name>
<email>nobuhiro.iwamatsu.yj@renesas.com</email>
</author>
<published>2010-06-07T07:55:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a5797a686f4c7cbced782959509d735cfa1344b1'/>
<id>a5797a686f4c7cbced782959509d735cfa1344b1</id>
<content type='text'>
In the change by 749da5f82fe33ff68dd4aa1a5e35cd9aa6246dab,
The change in the status when the USB device is connected is wrong.
Therefore, the device is not recognized.

Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Yoshihiro Shimoda &lt;shimoda.yoshihiro@renesas.com&gt;
CC: Paul Mundt" &lt;lethal@linux-sh.org&gt;
Signed-off-by: Nobuhiro Iwamatsu &lt;nobuhiro.iwamatsu.yj@renesas.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In the change by 749da5f82fe33ff68dd4aa1a5e35cd9aa6246dab,
The change in the status when the USB device is connected is wrong.
Therefore, the device is not recognized.

Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Yoshihiro Shimoda &lt;shimoda.yoshihiro@renesas.com&gt;
CC: Paul Mundt" &lt;lethal@linux-sh.org&gt;
Signed-off-by: Nobuhiro Iwamatsu &lt;nobuhiro.iwamatsu.yj@renesas.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: xHCI: Fix bug in link TRB activation change.</title>
<updated>2010-06-30T15:16:05+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2010-06-10T19:25:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6cc30d85a5bf61248ff0e1f0e0f15fe718bae378'/>
<id>6cc30d85a5bf61248ff0e1f0e0f15fe718bae378</id>
<content type='text'>
Commit 6c12db90f19727c76990e7f4801c67a148b30111 introduced a bug for
control transfers.  The patch was supposed to change when the link TRBs at
the end of each ring segment were given to the hardware.  If a transfer
descriptor (TD) ended just before the link TRB, the code wouldn't give
back the link TRB to the hardware; instead it would be given back in
prepare_ring() just before the next TD was enqueued at the top of the
ring.

Unfortunately, the code relied on checking the chain bit of the TRB to
determine whether the TD ended just before the link TRB.  It assumed that
the ring enqueuing code would call prepare_ring() before enqueuing the
next TD.  However, control transfers are made of multiple TDs, and
prepare_ring() is only called once before enqueuing two or three TDs.

If the first or second TD of the control transfer ended just before the
link TRB, then the code in inc_enq() would not move the enqueue pointer
past the link TRB, and the link TRB would get overwritten.  This would
cause the xHCI driver to start writing to memory past the ring segment,
and eventually the system would crash or hang.

The fix is to add a flag to inc_enq() that says whether the caller will
enqueue more TDs before calling prepare_ring().  If the chain bit is
cleared (meaning this is the last TRB in a TD), and the caller will not
enqueue more TDs, then we defer giving back the link TRB.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 6c12db90f19727c76990e7f4801c67a148b30111 introduced a bug for
control transfers.  The patch was supposed to change when the link TRBs at
the end of each ring segment were given to the hardware.  If a transfer
descriptor (TD) ended just before the link TRB, the code wouldn't give
back the link TRB to the hardware; instead it would be given back in
prepare_ring() just before the next TD was enqueued at the top of the
ring.

Unfortunately, the code relied on checking the chain bit of the TRB to
determine whether the TD ended just before the link TRB.  It assumed that
the ring enqueuing code would call prepare_ring() before enqueuing the
next TD.  However, control transfers are made of multiple TDs, and
prepare_ring() is only called once before enqueuing two or three TDs.

If the first or second TD of the control transfer ended just before the
link TRB, then the code in inc_enq() would not move the enqueue pointer
past the link TRB, and the link TRB would get overwritten.  This would
cause the xHCI driver to start writing to memory past the ring segment,
and eventually the system would crash or hang.

The fix is to add a flag to inc_enq() that says whether the caller will
enqueue more TDs before calling prepare_ring().  If the chain bit is
cleared (meaning this is the last TRB in a TD), and the caller will not
enqueue more TDs, then we defer giving back the link TRB.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
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