Hi, On Thu, Jul 18, 2013 at 04:33:43PM +0800, Rong Wang wrote: > On Wed, Jul 17, 2013 at 9:27 PM, Felipe Balbi <balbi@xxxxxx> wrote: > > On Wed, Jul 17, 2013 at 09:04:54PM +0800, Rong Wang wrote: > >> Hi Felipe, > >> > >> On Wed, Jul 17, 2013 at 3:57 PM, Felipe Balbi <balbi@xxxxxx> wrote: > >> > Hi, > >> > > >> > On Mon, Jul 15, 2013 at 11:31:17PM -0700, Greg KH wrote: > >> >> > The question is since we default GADGET, so the g_mass_storage.ko is > >> >> > installed early but connecting to a host PC > >> >> > is randomly, But the udev has no idea when a host PC connects our device. > >> >> > > >> >> > So we consider it's reasonable to let the udev know the GADGET device state. > >> >> > Is there any alternative to our question? > >> >> > >> >> I thought we already export events for gadget device states, have you > >> >> looked for them? I can't dig through the code at the moment, but this > >> >> seems like a pretty common issue... > >> >> > >> >> Felipe, any ideas? > >> > > >> > we already expose that in sysfs. IIRC udev can act on sysfs changes, > >> > no ? > >> > >> I do not know if udev can polling sysfs file content change. I'll study this. > >> > >> But the change is triggered by calling usb_gadget_set_state, and I find > >> composite framework do not call this. Then we should do this common work > >> in every udc driver? > > > > yes. Only the UDC driver knows when the controller is moving among those > > states. > > OK. I got that. > > But I think it may be more reasonable for the udc driver to maintain a > work queue > to handle the state change since this operation mostly happen in ISR ? And that's the patch I want to test. Adding a workqueue to every single UDC will be too much, so I tried to hide it in udc-core.c. I agree with you we need to pass the sysfs_notification to a separate workqueue though. If you can test the patch below, that would be great. commit d32521bd775d48b600e67f23d363d70f71597ffd Author: Felipe Balbi <balbi@xxxxxx> Date: Wed Jul 17 11:09:49 2013 +0300 usb: gadget: udc-core: move sysfs_notify() to a workqueue usb_gadget_set_state() will call sysfs_notify() which might sleep. Some users might want to call usb_gadget_set_state() from the very IRQ handler which actually changes the gadget state. Instead of having every UDC driver add their own workqueue for such a simple notification, we're adding it generically to our struct usb_gadget, so the details are hidden from all UDC drivers. Signed-off-by: Felipe Balbi <balbi@xxxxxx> diff --git a/drivers/usb/gadget/udc-core.c b/drivers/usb/gadget/udc-core.c index ffd8fa5..b0d91b1 100644 --- a/drivers/usb/gadget/udc-core.c +++ b/drivers/usb/gadget/udc-core.c @@ -23,6 +23,7 @@ #include <linux/list.h> #include <linux/err.h> #include <linux/dma-mapping.h> +#include <linux/workqueue.h> #include <linux/usb/ch9.h> #include <linux/usb/gadget.h> @@ -101,11 +102,18 @@ EXPORT_SYMBOL_GPL(usb_gadget_unmap_request); /* ------------------------------------------------------------------------- */ +static void usb_gadget_state_work(struct work_struct *work) +{ + struct usb_gadget *gadget = work_to_gadget(work); + + sysfs_notify(&gadget->dev.kobj, NULL, "status"); +} + void usb_gadget_set_state(struct usb_gadget *gadget, enum usb_device_state state) { gadget->state = state; - sysfs_notify(&gadget->dev.kobj, NULL, "status"); + schedule_work(&gadget->work); } EXPORT_SYMBOL_GPL(usb_gadget_set_state); @@ -192,6 +200,7 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget, goto err1; dev_set_name(&gadget->dev, "gadget"); + INIT_WORK(&gadget->work, usb_gadget_state_work); gadget->dev.parent = parent; dma_set_coherent_mask(&gadget->dev, parent->coherent_dma_mask); diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index f1b0dca..942ef5e 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -22,6 +22,7 @@ #include <linux/slab.h> #include <linux/scatterlist.h> #include <linux/types.h> +#include <linux/workqueue.h> #include <linux/usb/ch9.h> struct usb_ep; @@ -475,6 +476,7 @@ struct usb_gadget_ops { /** * struct usb_gadget - represents a usb slave device + * @work: (internal use) Workqueue to be used for sysfs_notify() * @ops: Function pointers used to access hardware-specific operations. * @ep0: Endpoint zero, used when reading or writing responses to * driver setup() requests @@ -520,6 +522,7 @@ struct usb_gadget_ops { * device is acting as a B-Peripheral (so is_a_peripheral is false). */ struct usb_gadget { + struct work_struct work; /* readonly to gadget driver */ const struct usb_gadget_ops *ops; struct usb_ep *ep0; @@ -538,6 +541,7 @@ struct usb_gadget { unsigned out_epnum; unsigned in_epnum; }; +#define work_to_gadget(w) (container_of((w), struct usb_gadget, work)) static inline void set_gadget_data(struct usb_gadget *gadget, void *data) { dev_set_drvdata(&gadget->dev, data); } -- balbi
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