tree 6abfa1d3a86f3a4f355e9dd11e6c8ee158a0202b
parent 45f23f189ca66d98b1f8b7f3d30a194d3188039d
author David Brownell <[EMAIL PROTECTED]> Tue, 19 Apr 2005 07:39:25 -0700
committer Greg K-H <[EMAIL PROTECTED]> Tue, 19 Apr 2005 07:39:25 -0700
[PATCH] USB: revert "fix" to usb_set_interface()
This reverts a recent change to usb_set_interface(). The change worked
around a quirk in certain devices, but doing this in usbcore creates
needless regressions for other devices. More appropriate fixes won't
put such handling in usbcore.
Basically it's tricky to do a full software reset of USB device state, since
the devices don't all act the same. This adds a note to the kerneldoc for
the usb_reset_configuration() call to highlight the quirk this was working
around: endpoint data toggles not being reset.
Signed-off-by: David Brownell <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
usb/core/message.c | 25 ++++---------------------
1 files changed, 4 insertions(+), 21 deletions(-)
Index: drivers/usb/core/message.c
===================================================================
--- 6fadab86aec4b6dd747ebfb316396842bf1501ab/drivers/usb/core/message.c
(mode:100644 sha1:40bdb38e7bcbade82a4a176344604947f5f2760a)
+++ 6abfa1d3a86f3a4f355e9dd11e6c8ee158a0202b/drivers/usb/core/message.c
(mode:100644 sha1:e12c5be1e0a345f12f430b17c17669ba32ba57f6)
@@ -1133,29 +1133,10 @@
/* prevent submissions using previous endpoint settings */
usb_disable_interface(dev, iface);
- /* 9.1.1.5 says:
- *
- * Configuring a device or changing an alternate setting
- * causes all of the status and configuration values
- * associated with endpoints in the affected interfaces to
- * be set to their default values. This includes setting
- * the data toggle of any endpoint using data toggles to
- * the value DATA0.
- *
- * Some devices take this too literally and don't reset the data
- * toggles if the new altsetting is the same as the old one (the
- * command isn't "changing" an alternate setting). We will manually
- * reset the toggles when the new and old altsettings are the same.
- * Most devices won't need this, but fortunately it doesn't happen
- * often.
- */
- if (iface->cur_altsetting == alt)
- manual = 1;
iface->cur_altsetting = alt;
/* If the interface only has one altsetting and the device didn't
- * accept the request (or whenever the old altsetting is the same
- * as the new one), we attempt to carry out the equivalent action
+ * accept the request, we attempt to carry out the equivalent action
* by manually clearing the HALT feature for each endpoint in the
* new altsetting.
*/
@@ -1202,7 +1183,9 @@
*
* Because this affects multiple interfaces, avoid using this with composite
* (multi-interface) devices. Instead, the driver for each interface may
- * use usb_set_interface() on the interfaces it claims. Resetting the whole
+ * use usb_set_interface() on the interfaces it claims. Be careful though;
+ * some devices don't support the SET_INTERFACE request, and others won't
+ * reset all the interface state (notably data toggles). Resetting the whole
* configuration would affect other drivers' interfaces.
*
* The caller must own the device lock.
-
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