[PATCH v4 1/7] usb: gadget: f_midi: Transmit data only when IN ep is enabled

From: Felipe F. Tonello
Date: Mon Oct 26 2015 - 12:58:21 EST


This makes sure f_midi doesn't try to enqueue data when the IN endpoint is
disabled, ie, USB cable is disconnected.

Signed-off-by: Felipe F. Tonello <eu@xxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_midi.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index edb84ca..e08f365 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -87,6 +87,7 @@ struct f_midi {
int index;
char *id;
unsigned int buflen, qlen;
+ bool in_ep_enabled;
};

static inline struct f_midi *func_to_midi(struct usb_function *f)
@@ -332,6 +333,7 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
err = f_midi_start_ep(midi, f, midi->in_ep);
if (err)
return err;
+ midi->in_ep_enabled = true;

err = f_midi_start_ep(midi, f, midi->out_ep);
if (err)
@@ -387,6 +389,8 @@ static void f_midi_disable(struct usb_function *f)
*/
usb_ep_disable(midi->in_ep);
usb_ep_disable(midi->out_ep);
+
+ midi->in_ep_enabled = false;
}

static int f_midi_snd_free(struct snd_device *device)
@@ -543,7 +547,7 @@ static void f_midi_transmit(struct f_midi *midi, struct usb_request *req)
}
}

- if (req->length > 0) {
+ if (req->length > 0 && midi->in_ep_enabled) {
int err;

err = usb_ep_queue(ep, req, GFP_ATOMIC);
@@ -1158,6 +1162,7 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
midi->index = opts->index;
midi->buflen = opts->buflen;
midi->qlen = opts->qlen;
+ midi->in_ep_enabled = false;
++opts->refcnt;
mutex_unlock(&opts->lock);

--
2.1.4

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