Sorry Greg, but your patch does not work, I tried using usb_bulk_msg()
in the first place but it returns -22 (-EINVAL) this is because the
pipe is not an interrupt pipe. Using usb_bulk_msg() does work on
another one of my machines, however.
A properly written solution would be a modified version of
usb_bulk_msg, not just a wrapper.
No {} needed for 1 line for statements (or if statements).
> printk("\n");
I guess I didn't make myself clear. I'm not looking for syntax advice,
this is only a rapid prototype. I'm looking for obvious faults that
may cause deadlock or a kernel panic.
> complete(&(dev->read_comp));
What does this completion handler do?
It unblocks the read function so it has synchronous support.
wait_for_completion(&(dev->read_comp) );
What happens if the interrupt completes before you get here? Hm, maybe
that will be safe, haven't looked at that in a long time, you might want
to verify this.
Good point, I guess I should check the status before doing a wait. I
figured that the completion would already be complete so
wait_for_completion would return immediately.
Anyone else?
-Paul
On 5/19/06, Greg KH <[EMAIL PROTECTED]> wrote:
On Fri, May 19, 2006 at 03:23:24PM -0700, Greg KH wrote:
> On Fri, May 19, 2006 at 01:21:52AM -0400, Paul Giblock wrote:
> > Hello, sorry about the last message. I figured it out on my own. I
> > was always sort of surprised that usb_bulk_msg would work fine with
> > interrupt endpoints, so it was just a matter of time until it would
> > not. Anyways, I solved the problem with a callback and a condition
> > variable.
No, it should work just fine. Look at the documentation for
usb_bulk_msg(). If something's wrong, let us know so we can fix it.
> Oh crap, we don't have a blocking usb_interrupt_msg() type function do
> we? I've wanted that for a long time, let me go add that to the core.
> That should do what you need, right?
Well, it is dirt simple, just for completion, here's the patch.
thanks,
greg k-h
---
drivers/usb/core/message.c | 30 ++++++++++++++++++++++++++++++
include/linux/usb.h | 2 ++
2 files changed, 32 insertions(+)
--- gregkh-2.6.orig/drivers/usb/core/message.c
+++ gregkh-2.6/drivers/usb/core/message.c
@@ -158,6 +158,36 @@ int usb_control_msg(struct usb_device *d
/**
+ * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for
completion
+ * @usb_dev: pointer to the usb device to send the message to
+ * @pipe: endpoint "pipe" to send the message to
+ * @data: pointer to the data to send
+ * @len: length in bytes of the data to send
+ * @actual_length: pointer to a location to put the actual length transferred
in bytes
+ * @timeout: time in msecs to wait for the message to complete before
+ * timing out (if 0 the wait is forever)
+ * Context: !in_interrupt ()
+ *
+ * This function sends a simple interrupt message to a specified endpoint and
+ * waits for the message to complete, or timeout.
+ *
+ * If successful, it returns 0, otherwise a negative error number. The number
+ * of actual bytes transferred will be stored in the actual_length paramater.
+ *
+ * Don't use this function from within an interrupt context, like a bottom half
+ * handler. If you need an asynchronous message, or need to send a message
+ * from within interrupt context, use usb_submit_urb() If a thread in your
+ * driver uses this call, make sure your disconnect() method can wait for it to
+ * complete. Since you don't have a handle on the URB used, you can't cancel
+ * the request.
+ */
+int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
+ void *data, int len, int *actual_length, int timeout)
+{
+ return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout);
+}
+
+/**
* usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
* @usb_dev: pointer to the usb device to send the message to
* @pipe: endpoint "pipe" to send the message to
--- gregkh-2.6.orig/include/linux/usb.h
+++ gregkh-2.6/include/linux/usb.h
@@ -1021,6 +1021,8 @@ void usb_buffer_unmap_sg (struct usb_dev
extern int usb_control_msg(struct usb_device *dev, unsigned int pipe,
__u8 request, __u8 requesttype, __u16 value, __u16 index,
void *data, __u16 size, int timeout);
+extern int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
+ void *data, int len, int *actual_length, int timeout);
extern int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
void *data, int len, int *actual_length,
int timeout);
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