<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/usb/core, branch v3.14.24</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: Do not allow usb_alloc_streams on unconfigured devices</title>
<updated>2014-11-14T17:00:07+00:00</updated>
<author>
<name>Hans de Goede</name>
<email>hdegoede@redhat.com</email>
</author>
<published>2014-10-01T09:29:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c0456439a33655d85de1136e09d9779e6d8f0b51'/>
<id>c0456439a33655d85de1136e09d9779e6d8f0b51</id>
<content type='text'>
commit 90a646c770c50cc206ceba0d7b50453c46c13c36 upstream.

This commit fixes the following oops:

[10238.622067] scsi host3: uas_eh_bus_reset_handler start
[10240.766164] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10245.779365] usb 3-4: device descriptor read/8, error -110
[10245.883331] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10250.897603] usb 3-4: device descriptor read/8, error -110
[10251.058200] BUG: unable to handle kernel NULL pointer dereference at  0000000000000040
[10251.058244] IP: [&lt;ffffffff815ac6e1&gt;] xhci_check_streams_endpoint+0x91/0x140
&lt;snip&gt;
[10251.059473] Call Trace:
[10251.059487]  [&lt;ffffffff815aca6c&gt;] xhci_calculate_streams_and_bitmask+0xbc/0x130
[10251.059520]  [&lt;ffffffff815aeb5f&gt;] xhci_alloc_streams+0x10f/0x5a0
[10251.059548]  [&lt;ffffffff810a4685&gt;] ? check_preempt_curr+0x75/0xa0
[10251.059575]  [&lt;ffffffff810a46dc&gt;] ? ttwu_do_wakeup+0x2c/0x100
[10251.059601]  [&lt;ffffffff810a49e6&gt;] ? ttwu_do_activate.constprop.111+0x66/0x70
[10251.059635]  [&lt;ffffffff815779ab&gt;] usb_alloc_streams+0xab/0xf0
[10251.059662]  [&lt;ffffffffc0616b48&gt;] uas_configure_endpoints+0x128/0x150 [uas]
[10251.059694]  [&lt;ffffffffc0616bac&gt;] uas_post_reset+0x3c/0xb0 [uas]
[10251.059722]  [&lt;ffffffff815727d9&gt;] usb_reset_device+0x1b9/0x2a0
[10251.059749]  [&lt;ffffffffc0616f42&gt;] uas_eh_bus_reset_handler+0xb2/0x190 [uas]
[10251.059781]  [&lt;ffffffff81514293&gt;] scsi_try_bus_reset+0x53/0x110
[10251.059808]  [&lt;ffffffff815163b7&gt;] scsi_eh_bus_reset+0xf7/0x270
&lt;snip&gt;

The problem is the following call sequence (simplified):

1) usb_reset_device
2)  usb_reset_and_verify_device
2)   hub_port_init
3)    hub_port_finish_reset
3)     xhci_discover_or_reset_device
        This frees xhci-&gt;devs[slot_id]-&gt;eps[ep_index].ring for all eps but 0
4)    usb_get_device_descriptor
       This fails
5)   hub_port_init fails
6)  usb_reset_and_verify_device fails, does not restore device config
7)  uas_post_reset
8)   xhci_alloc_streams
      NULL deref on the free-ed ring

This commit fixes this by not allowing usb_alloc_streams to continue if
the device is not configured.

Note that we do allow usb_free_streams to continue after a (logical)
disconnect, as it is necessary to explicitly free the streams at the xhci
controller level.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 90a646c770c50cc206ceba0d7b50453c46c13c36 upstream.

This commit fixes the following oops:

[10238.622067] scsi host3: uas_eh_bus_reset_handler start
[10240.766164] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10245.779365] usb 3-4: device descriptor read/8, error -110
[10245.883331] usb 3-4: reset SuperSpeed USB device number 3 using xhci_hcd
[10250.897603] usb 3-4: device descriptor read/8, error -110
[10251.058200] BUG: unable to handle kernel NULL pointer dereference at  0000000000000040
[10251.058244] IP: [&lt;ffffffff815ac6e1&gt;] xhci_check_streams_endpoint+0x91/0x140
&lt;snip&gt;
[10251.059473] Call Trace:
[10251.059487]  [&lt;ffffffff815aca6c&gt;] xhci_calculate_streams_and_bitmask+0xbc/0x130
[10251.059520]  [&lt;ffffffff815aeb5f&gt;] xhci_alloc_streams+0x10f/0x5a0
[10251.059548]  [&lt;ffffffff810a4685&gt;] ? check_preempt_curr+0x75/0xa0
[10251.059575]  [&lt;ffffffff810a46dc&gt;] ? ttwu_do_wakeup+0x2c/0x100
[10251.059601]  [&lt;ffffffff810a49e6&gt;] ? ttwu_do_activate.constprop.111+0x66/0x70
[10251.059635]  [&lt;ffffffff815779ab&gt;] usb_alloc_streams+0xab/0xf0
[10251.059662]  [&lt;ffffffffc0616b48&gt;] uas_configure_endpoints+0x128/0x150 [uas]
[10251.059694]  [&lt;ffffffffc0616bac&gt;] uas_post_reset+0x3c/0xb0 [uas]
[10251.059722]  [&lt;ffffffff815727d9&gt;] usb_reset_device+0x1b9/0x2a0
[10251.059749]  [&lt;ffffffffc0616f42&gt;] uas_eh_bus_reset_handler+0xb2/0x190 [uas]
[10251.059781]  [&lt;ffffffff81514293&gt;] scsi_try_bus_reset+0x53/0x110
[10251.059808]  [&lt;ffffffff815163b7&gt;] scsi_eh_bus_reset+0xf7/0x270
&lt;snip&gt;

The problem is the following call sequence (simplified):

1) usb_reset_device
2)  usb_reset_and_verify_device
2)   hub_port_init
3)    hub_port_finish_reset
3)     xhci_discover_or_reset_device
        This frees xhci-&gt;devs[slot_id]-&gt;eps[ep_index].ring for all eps but 0
4)    usb_get_device_descriptor
       This fails
5)   hub_port_init fails
6)  usb_reset_and_verify_device fails, does not restore device config
7)  uas_post_reset
8)   xhci_alloc_streams
      NULL deref on the free-ed ring

This commit fixes this by not allowing usb_alloc_streams to continue if
the device is not configured.

Note that we do allow usb_free_streams to continue after a (logical)
disconnect, as it is necessary to explicitly free the streams at the xhci
controller level.

Signed-off-by: Hans de Goede &lt;hdegoede@redhat.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: quirks: enable device-qualifier quirk for yet another Elan touchscreen</title>
<updated>2014-11-14T17:00:06+00:00</updated>
<author>
<name>Adel Gadllah</name>
<email>adel.gadllah@gmail.com</email>
</author>
<published>2014-10-09T07:29:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2a5082de38b2c790dbf157b24e384578b0db9657'/>
<id>2a5082de38b2c790dbf157b24e384578b0db9657</id>
<content type='text'>
commit d749947561af5996ccc076b2ffcc5f48b1be5d74 upstream.

Yet another device affected by this.

Tested-by: Kevin Fenzi &lt;kevin@scrye.com&gt;
Signed-off-by: Adel Gadllah &lt;adel.gadllah@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d749947561af5996ccc076b2ffcc5f48b1be5d74 upstream.

Yet another device affected by this.

Tested-by: Kevin Fenzi &lt;kevin@scrye.com&gt;
Signed-off-by: Adel Gadllah &lt;adel.gadllah@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: quirks: enable device-qualifier quirk for another Elan touchscreen</title>
<updated>2014-11-14T17:00:05+00:00</updated>
<author>
<name>Adel Gadllah</name>
<email>adel.gadllah@gmail.com</email>
</author>
<published>2014-10-09T07:29:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f825efc93baaf9e9a718fa67be8e661298cf8702'/>
<id>f825efc93baaf9e9a718fa67be8e661298cf8702</id>
<content type='text'>
commit 876af5d454548be40327ba9efea4bc92a8575019 upstream.

Currently this quirk is enabled for the model with the device id 0x0089, it
is needed for the 0x009b model, which is found on the Fujitsu Lifebook u904
as well.

Signed-off-by: Adel Gadllah &lt;adel.gadllah@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 876af5d454548be40327ba9efea4bc92a8575019 upstream.

Currently this quirk is enabled for the model with the device id 0x0089, it
is needed for the 0x009b model, which is found on the Fujitsu Lifebook u904
as well.

Signed-off-by: Adel Gadllah &lt;adel.gadllah@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: quirks: enable device-qualifier quirk for Elan Touchscreen</title>
<updated>2014-11-14T17:00:05+00:00</updated>
<author>
<name>Johan Hovold</name>
<email>johan@kernel.org</email>
</author>
<published>2014-08-25T15:51:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=16830f2a51fc85f53cd9527a13f979f8c2e70370'/>
<id>16830f2a51fc85f53cd9527a13f979f8c2e70370</id>
<content type='text'>
commit c68929f75dfcb6354918862b91b5778585de1fa5 upstream.

Enable device-qualifier quirk for Elan Touchscreen, which often fails to
handle requests for the device_descriptor.

Note that the device sometimes do respond properly with a Request Error
(three times as USB core retries), but usually fails to respond at all.
When this happens any further descriptor requests also fails, for
example:

[ 1528.688934] usb 2-7: new full-speed USB device number 4 using xhci_hcd
[ 1530.945588] usb 2-7: unable to read config index 0 descriptor/start: -71
[ 1530.945592] usb 2-7: can't read configurations, error -71

This has been observed repeating for over a minute before eventual
successful enumeration.

Reported-by: Drew Von Spreecken &lt;drewvs@gmail.com&gt;
Reported-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c68929f75dfcb6354918862b91b5778585de1fa5 upstream.

Enable device-qualifier quirk for Elan Touchscreen, which often fails to
handle requests for the device_descriptor.

Note that the device sometimes do respond properly with a Request Error
(three times as USB core retries), but usually fails to respond at all.
When this happens any further descriptor requests also fails, for
example:

[ 1528.688934] usb 2-7: new full-speed USB device number 4 using xhci_hcd
[ 1530.945588] usb 2-7: unable to read config index 0 descriptor/start: -71
[ 1530.945592] usb 2-7: can't read configurations, error -71

This has been observed repeating for over a minute before eventual
successful enumeration.

Reported-by: Drew Von Spreecken &lt;drewvs@gmail.com&gt;
Reported-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: add device-qualifier quirk</title>
<updated>2014-11-14T17:00:05+00:00</updated>
<author>
<name>Johan Hovold</name>
<email>johan@kernel.org</email>
</author>
<published>2014-08-25T15:51:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=98bc9c6c6d459e252d27549492be6c4603ff2a3e'/>
<id>98bc9c6c6d459e252d27549492be6c4603ff2a3e</id>
<content type='text'>
commit 2a159389bf5d962359349a76827b2f683276a1c7 upstream.

Add new quirk for devices that cannot handle requests for the
device_qualifier descriptor.

A USB-2.0 compliant device must respond to requests for the
device_qualifier descriptor (even if it's with a request error), but at
least one device is known to misbehave after such a request.

Suggested-by: Bjørn Mork &lt;bjorn@mork.no&gt;
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2a159389bf5d962359349a76827b2f683276a1c7 upstream.

Add new quirk for devices that cannot handle requests for the
device_qualifier descriptor.

A USB-2.0 compliant device must respond to requests for the
device_qualifier descriptor (even if it's with a request error), but at
least one device is known to misbehave after such a request.

Suggested-by: Bjørn Mork &lt;bjorn@mork.no&gt;
Signed-off-by: Johan Hovold &lt;johan@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Add device quirk for ASUS T100 Base Station keyboard</title>
<updated>2014-10-15T06:36:43+00:00</updated>
<author>
<name>Lu Baolu</name>
<email>baolu.lu@linux.intel.com</email>
</author>
<published>2014-09-19T02:13:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5b1ab22ac108be2d89e47303a76a76fe10fe00b1'/>
<id>5b1ab22ac108be2d89e47303a76a76fe10fe00b1</id>
<content type='text'>
commit ddbe1fca0bcb87ca8c199ea873a456ca8a948567 upstream.

This full-speed USB device generates spurious remote wakeup event
as soon as USB_DEVICE_REMOTE_WAKEUP feature is set. As the result,
Linux can't enter system suspend and S0ix power saving modes once
this keyboard is used.

This patch tries to introduce USB_QUIRK_IGNORE_REMOTE_WAKEUP quirk.
With this quirk set, wakeup capability will be ignored during
device configure.

This patch could be back-ported to kernels as old as 2.6.39.

Signed-off-by: Lu Baolu &lt;baolu.lu@linux.intel.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ddbe1fca0bcb87ca8c199ea873a456ca8a948567 upstream.

This full-speed USB device generates spurious remote wakeup event
as soon as USB_DEVICE_REMOTE_WAKEUP feature is set. As the result,
Linux can't enter system suspend and S0ix power saving modes once
this keyboard is used.

This patch tries to introduce USB_QUIRK_IGNORE_REMOTE_WAKEUP quirk.
With this quirk set, wakeup capability will be ignored during
device configure.

This patch could be back-ported to kernels as old as 2.6.39.

Signed-off-by: Lu Baolu &lt;baolu.lu@linux.intel.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>usb: hub: take hub-&gt;hdev reference when processing from eventlist</title>
<updated>2014-10-05T21:52:15+00:00</updated>
<author>
<name>Joe Lawrence</name>
<email>joe.lawrence@stratus.com</email>
</author>
<published>2014-09-10T19:07:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3f6622c77fe9a0bc5ed668e5e9b03944e3cd80a4'/>
<id>3f6622c77fe9a0bc5ed668e5e9b03944e3cd80a4</id>
<content type='text'>
commit c605f3cdff53a743f6d875b76956b239deca1272 upstream.

During surprise device hotplug removal tests, it was observed that
hub_events may try to call usb_lock_device on a device that has already
been freed. Protect the usb_device by taking out a reference (under the
hub_event_lock) when hub_events pulls it off the list, returning the
reference after hub_events is finished using it.

Signed-off-by: Joe Lawrence &lt;joe.lawrence@stratus.com&gt;
Suggested-by: David Bulkow &lt;david.bulkow@stratus.com&gt; for using kref
Suggested-by: Alan Stern &lt;stern@rowland.harvard.edu&gt; for placement
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c605f3cdff53a743f6d875b76956b239deca1272 upstream.

During surprise device hotplug removal tests, it was observed that
hub_events may try to call usb_lock_device on a device that has already
been freed. Protect the usb_device by taking out a reference (under the
hub_event_lock) when hub_events pulls it off the list, returning the
reference after hub_events is finished using it.

Signed-off-by: Joe Lawrence &lt;joe.lawrence@stratus.com&gt;
Suggested-by: David Bulkow &lt;david.bulkow@stratus.com&gt; for using kref
Suggested-by: Alan Stern &lt;stern@rowland.harvard.edu&gt; for placement
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: fix build error with CONFIG_PM_RUNTIME disabled</title>
<updated>2014-09-05T23:34:18+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2014-08-27T23:55:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=472faa93165a83df31af25f9097b23c981d26968'/>
<id>472faa93165a83df31af25f9097b23c981d26968</id>
<content type='text'>
commit a9ef803d740bfadf5e505fbc57efa57692e27025 upstream.

commit bdd405d2a528 ("usb: hub: Prevent hub autosuspend if
usbcore.autosuspend is -1") causes a build error if CONFIG_PM_RUNTIME is
disabled.  Fix that by doing a simple #ifdef guard around it.

Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Reported-by: kbuild test robot &lt;fengguang.wu@intel.com&gt;
Cc: Roger Quadros &lt;rogerq@ti.com&gt;
Cc: Michael Welling &lt;mwelling@emacinc.com&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a9ef803d740bfadf5e505fbc57efa57692e27025 upstream.

commit bdd405d2a528 ("usb: hub: Prevent hub autosuspend if
usbcore.autosuspend is -1") causes a build error if CONFIG_PM_RUNTIME is
disabled.  Fix that by doing a simple #ifdef guard around it.

Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Reported-by: kbuild test robot &lt;fengguang.wu@intel.com&gt;
Cc: Roger Quadros &lt;rogerq@ti.com&gt;
Cc: Michael Welling &lt;mwelling@emacinc.com&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>usb: hub: Prevent hub autosuspend if usbcore.autosuspend is -1</title>
<updated>2014-09-05T23:34:18+00:00</updated>
<author>
<name>Roger Quadros</name>
<email>rogerq@ti.com</email>
</author>
<published>2014-08-04T09:44:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=323308e6f5ea6e0fa311478581c87b09fa219f9c'/>
<id>323308e6f5ea6e0fa311478581c87b09fa219f9c</id>
<content type='text'>
commit bdd405d2a5287bdb9b04670ea255e1f122138e66 upstream.

If user specifies that USB autosuspend must be disabled by module
parameter "usbcore.autosuspend=-1" then we must prevent
autosuspend of USB hub devices as well.

commit 596d789a211d introduced in v3.8 changed the original behaivour
and stopped respecting the usbcore.autosuspend parameter for hubs.

Fixes: 596d789a211d "USB: set hub's default autosuspend delay as 0"

Signed-off-by: Roger Quadros &lt;rogerq@ti.com&gt;
Tested-by: Michael Welling &lt;mwelling@emacinc.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit bdd405d2a5287bdb9b04670ea255e1f122138e66 upstream.

If user specifies that USB autosuspend must be disabled by module
parameter "usbcore.autosuspend=-1" then we must prevent
autosuspend of USB hub devices as well.

commit 596d789a211d introduced in v3.8 changed the original behaivour
and stopped respecting the usbcore.autosuspend parameter for hubs.

Fixes: 596d789a211d "USB: set hub's default autosuspend delay as 0"

Signed-off-by: Roger Quadros &lt;rogerq@ti.com&gt;
Tested-by: Michael Welling &lt;mwelling@emacinc.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Fix persist resume of some SS USB devices</title>
<updated>2014-09-05T23:34:13+00:00</updated>
<author>
<name>Pratyush Anand</name>
<email>pratyush.anand@st.com</email>
</author>
<published>2014-07-18T07:07:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d70593c4dc3484e58b27e90a673fec8db7c75c19'/>
<id>d70593c4dc3484e58b27e90a673fec8db7c75c19</id>
<content type='text'>
commit a40178b2fa6ad87670fb1e5fa4024db00c149629 upstream.

Problem Summary: Problem has been observed generally with PM states
where VBUS goes off during suspend. There are some SS USB devices which
take longer time for link training compared to many others.  Such
devices fail to reconnect with same old address which was associated
with it before suspend.

When system resumes, at some point of time (dpm_run_callback-&gt;
usb_dev_resume-&gt;usb_resume-&gt;usb_resume_both-&gt;usb_resume_device-&gt;
usb_port_resume) SW reads hub status. If device is present,
then it finishes port resume and re-enumerates device with same
address. If device is not present then, SW thinks that device was
removed during suspend and therefore does logical disconnection
and removes all the resource allocated for this device.

Now, if I put sufficient delay just before root hub status read in
usb_resume_device then, SW sees always that device is present. In normal
course(without any delay) SW sees that no device is present and then SW
removes all resource associated with the device at this port.  In the
latter case, after sometime, device says that hey I am here, now host
enumerates it, but with new address.

Problem had been reproduced when I connect verbatim USB3.0 hard disc
with my STiH407 XHCI host running with 3.10 kernel.

I see that similar problem has been reported here.
https://bugzilla.kernel.org/show_bug.cgi?id=53211
Reading above it seems that bug was not in 3.6.6 and was present in 3.8
and again it was not present for some in 3.12.6, while it was present
for few others. I tested with 3.13-FC19 running at i686 desktop, problem
was still there. However, I was failed to reproduce it with 3.16-RC4
running at same i686 machine. I would say it is just a random
observation. Problem for few devices is always there, as I am unable to
find a proper fix for the issue.

So, now question is what should be the amount of delay so that host is
always able to recognize suspended device after resume.

XHCI specs 4.19.4 says that when Link training is successful, port sets
CSC bit to 1. So if SW reads port status before successful link
training, then it will not find device to be present.  USB Analyzer log
with such buggy devices show that in some cases device switch on the
RX termination after long delay of host enabling the VBUS. In few other
cases it has been seen that device fails to negotiate link training in
first attempt. It has been reported till now that few devices take as
long as 2000 ms to train the link after host enabling its VBUS and
RX termination. This patch implements a 2000 ms timeout for CSC bit to set
ie for link training. If in a case link trains before timeout, loop will
exit earlier.

This patch implements above delay, but only for SS device and when
persist is enabled.

So, for the good device overhead is almost none. While for the bad
devices penalty could be the time which it take for link training.
But, If a device was connected before suspend, and was removed
while system was asleep, then the penalty would be the timeout ie
2000 ms.

Results:

Verbatim USB SS hard disk connected with STiH407 USB host running 3.10
Kernel resumes in 461 msecs without this patch, but hard disk is
assigned a new device address. Same system resumes in 790 msecs with
this patch, but with old device address.

Signed-off-by: Pratyush Anand &lt;pratyush.anand@st.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a40178b2fa6ad87670fb1e5fa4024db00c149629 upstream.

Problem Summary: Problem has been observed generally with PM states
where VBUS goes off during suspend. There are some SS USB devices which
take longer time for link training compared to many others.  Such
devices fail to reconnect with same old address which was associated
with it before suspend.

When system resumes, at some point of time (dpm_run_callback-&gt;
usb_dev_resume-&gt;usb_resume-&gt;usb_resume_both-&gt;usb_resume_device-&gt;
usb_port_resume) SW reads hub status. If device is present,
then it finishes port resume and re-enumerates device with same
address. If device is not present then, SW thinks that device was
removed during suspend and therefore does logical disconnection
and removes all the resource allocated for this device.

Now, if I put sufficient delay just before root hub status read in
usb_resume_device then, SW sees always that device is present. In normal
course(without any delay) SW sees that no device is present and then SW
removes all resource associated with the device at this port.  In the
latter case, after sometime, device says that hey I am here, now host
enumerates it, but with new address.

Problem had been reproduced when I connect verbatim USB3.0 hard disc
with my STiH407 XHCI host running with 3.10 kernel.

I see that similar problem has been reported here.
https://bugzilla.kernel.org/show_bug.cgi?id=53211
Reading above it seems that bug was not in 3.6.6 and was present in 3.8
and again it was not present for some in 3.12.6, while it was present
for few others. I tested with 3.13-FC19 running at i686 desktop, problem
was still there. However, I was failed to reproduce it with 3.16-RC4
running at same i686 machine. I would say it is just a random
observation. Problem for few devices is always there, as I am unable to
find a proper fix for the issue.

So, now question is what should be the amount of delay so that host is
always able to recognize suspended device after resume.

XHCI specs 4.19.4 says that when Link training is successful, port sets
CSC bit to 1. So if SW reads port status before successful link
training, then it will not find device to be present.  USB Analyzer log
with such buggy devices show that in some cases device switch on the
RX termination after long delay of host enabling the VBUS. In few other
cases it has been seen that device fails to negotiate link training in
first attempt. It has been reported till now that few devices take as
long as 2000 ms to train the link after host enabling its VBUS and
RX termination. This patch implements a 2000 ms timeout for CSC bit to set
ie for link training. If in a case link trains before timeout, loop will
exit earlier.

This patch implements above delay, but only for SS device and when
persist is enabled.

So, for the good device overhead is almost none. While for the bad
devices penalty could be the time which it take for link training.
But, If a device was connected before suspend, and was removed
while system was asleep, then the penalty would be the timeout ie
2000 ms.

Results:

Verbatim USB SS hard disk connected with STiH407 USB host running 3.10
Kernel resumes in 461 msecs without this patch, but hard disk is
assigned a new device address. Same system resumes in 790 msecs with
this patch, but with old device address.

Signed-off-by: Pratyush Anand &lt;pratyush.anand@st.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
