This is a note to let you know that I've just added the patch titled
usb: musb: call musb_start() only once in OTG mode
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-musb-call-musb_start-only-once-in-otg-mode.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ae44df2e21b50f9fff28ac75c57e399c04df812c Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Date: Tue, 15 Oct 2013 18:29:22 +0200
Subject: usb: musb: call musb_start() only once in OTG mode
From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
commit ae44df2e21b50f9fff28ac75c57e399c04df812c upstream.
In commit 001dd84 ("usb: musb: start musb on the udc side, too") it was
ensured that the state engine is started also in OTG mode after a
removal / insertion of the gadget.
Unfortunately this change also introduced a bug: If the device is
configured as OTG and it connected with a remote host _without_ loading
a gadget then we bug() later (because musb->otg->gadget is not
initialized).
Initially I assumed it might be nice to have the host part of musb in
OTG mode working without having a gadget loaded. This bug and fact that
it wasn't working like this before the host/gadget split made me realize
that this was a silly idea.
This patch now introduces back the old behavior where in OTG mode the
host mode is only working after the gadget has been loaded.
Cc: Daniel Mack <zonque@xxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/musb/musb_virthub.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
--- a/drivers/usb/musb/musb_virthub.c
+++ b/drivers/usb/musb/musb_virthub.c
@@ -220,6 +220,23 @@ int musb_hub_status_data(struct usb_hcd
return retval;
}
+static int musb_has_gadget(struct musb *musb)
+{
+ /*
+ * In host-only mode we start a connection right away. In OTG mode
+ * we have to wait until we loaded a gadget. We don't really need a
+ * gadget if we operate as a host but we should not start a session
+ * as a device without a gadget or else we explode.
+ */
+#ifdef CONFIG_USB_MUSB_HOST
+ return 1;
+#else
+ if (musb->port_mode == MUSB_PORT_MODE_HOST)
+ return 1;
+ return musb->g.dev.driver != NULL;
+#endif
+}
+
int musb_hub_control(
struct usb_hcd *hcd,
u16 typeReq,
@@ -362,7 +379,7 @@ int musb_hub_control(
* initialization logic, e.g. for OTG, or change any
* logic relating to VBUS power-up.
*/
- if (!hcd->self.is_b_host)
+ if (!hcd->self.is_b_host && musb_has_gadget(musb))
musb_start(musb);
break;
case USB_PORT_FEAT_RESET:
Patches currently in stable-queue which might be from bigeasy@xxxxxxxxxxxxx are
queue-3.12/usb-musb-call-musb_start-only-once-in-otg-mode.patch
queue-3.12/usb-musb-core-properly-free-host-device-structs-in-err-path.patch
queue-3.12/usb-musb-cancel-work-on-removal.patch
queue-3.12/usb-musb-dsps-move-try_idle-to-start-hook.patch
queue-3.12/usb-musb-dsps-redo-the-otg-timer.patch
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