[PATCH 2/7 v3] initdev:kernel:USB init device discovery notification

[PATCH 2/7 v3] initdev:kernel:USB init device discovery notification

[David VomLehn]

From: Alan Stern <stern@rowland.harvard.edu>

Use init device discovery infrastructure to provide notification of
availability of USB devices.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: David VomLehn <dvomlehn@cisco.com>
---
 drivers/usb/core/hub.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index be86ae3..08baee0 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -37,6 +37,20 @@
 #endif
 #endif
 
+/* The mask of possible USB boot devices depends on what drivers and
+ * options have been configured into the kernel.  There are too many
+ * USB network config options to list here, so just assume it is always
+ * possible to have a USB network device.
+ */
+static int usb_initdev_mask = 0
+#ifdef CONFIG_USB_SERIAL_CONSOLE
+				| INITDEV_CONSOLE_MASK
+#endif
+#if defined(CONFIG_USB_STORAGE) || defined(CONFIG_BLK_DEV_UB)
+				| INITDEV_BLOCK_MASK
+#endif
+				| INITDEV_NETDEV_MASK;
+
 struct usb_hub {
 	struct device		*intfdev;	/* the "interface" device */
 	struct usb_device	*hdev;
@@ -73,6 +87,7 @@ struct usb_hub {
 	unsigned		limited_power:1;
 	unsigned		quiescing:1;
 	unsigned		disconnected:1;
+	unsigned		probing:1;
 
 	unsigned		has_indicators:1;
 	u8			indicator[USB_MAXCHILDREN];
@@ -1079,6 +1094,9 @@ static int hub_configure(struct usb_hub *hub,
 	if (hub->has_indicators && blinkenlights)
 		hub->indicator [0] = INDICATOR_CYCLE;
 
+	hub->probing = 1;
+	initdev_found(usb_initdev_mask);
+
 	hub_activate(hub, HUB_INIT);
 	return 0;
 
@@ -1124,6 +1142,9 @@ static void hub_disconnect(struct usb_interface *intf)
 	usb_buffer_free(hub->hdev, sizeof(*hub->buffer), hub->buffer,
 			hub->buffer_dma);
 
+	if (hub->probing)
+		initdev_probe_done(usb_initdev_mask);
+
 	kref_put(&hub->kref, hub_release);
 }
 
@@ -3135,6 +3156,11 @@ static void hub_events(void)
 						portstatus, portchange);
 		} /* end for i */
 
+		if (hub->probing) {
+			hub->probing = 0;
+			initdev_probe_done(usb_initdev_mask);
+		}
+
 		/* deal with hub status changes */
 		if (test_and_clear_bit(0, hub->event_bits) == 0)
 			;	/* do nothing */

Re: [PATCH 2/7 v3] initdev:kernel:USB init device discovery notification

[Alan Jenkins]

On 8/4/09, David VomLehn <dvomlehn@cisco.com> wrote:
> From: Alan Stern <stern@rowland.harvard.edu>
>
> Use init device discovery infrastructure to provide notification of
> availability of USB devices.
>
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> Signed-off-by: David VomLehn <dvomlehn@cisco.com>
> ---
>  drivers/usb/core/hub.c |   26 ++++++++++++++++++++++++++
>  1 files changed, 26 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index be86ae3..08baee0 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -37,6 +37,20 @@
>  #endif
>  #endif
>
> +/* The mask of possible USB boot devices depends on what drivers and
> + * options have been configured into the kernel.  There are too many
> + * USB network config options to list here, so just assume it is always
> + * possible to have a USB network device.
> + */

That could be fixed though.  Make the "USB Network Adaptors" menu into
an option.  Then you just have e.g. "CONFIG_NETDEV_USB", plus the two
class devices outside the menu (CONFIG_USB_ACM and CONFIG_USB_WDM).

Alan

Re: [PATCH 2/7 v3] initdev:kernel:USB init device discovery notification

[Alan Stern]

On Fri, 7 Aug 2009, Alan Jenkins wrote:

> > +/* The mask of possible USB boot devices depends on what drivers and
> > + * options have been configured into the kernel.  There are too many
> > + * USB network config options to list here, so just assume it is always
> > + * possible to have a USB network device.
> > + */
> 
> That could be fixed though.  Make the "USB Network Adaptors" menu into
> an option.  Then you just have e.g. "CONFIG_NETDEV_USB", plus the two
> class devices outside the menu (CONFIG_USB_ACM and CONFIG_USB_WDM).

That could be done.  It might even meet with the approval of the
networking maintainer, independent of this patch series.

But what if somebody adds yet another networking class driver outside
the menu?

Alan Stern

Re: [PATCH 2/7 v3] initdev:kernel:USB init device discovery notification

[Alan Jenkins]

On 8/7/09, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Fri, 7 Aug 2009, Alan Jenkins wrote:
>
>> > +/* The mask of possible USB boot devices depends on what drivers and
>> > + * options have been configured into the kernel.  There are too many
>> > + * USB network config options to list here, so just assume it is always
>> > + * possible to have a USB network device.
>> > + */
>>
>> That could be fixed though.  Make the "USB Network Adaptors" menu into
>> an option.  Then you just have e.g. "CONFIG_NETDEV_USB", plus the two
>> class devices outside the menu (CONFIG_USB_ACM and CONFIG_USB_WDM).

Oops, scratch WDM.  It doesn't actually provide a network device
(otherwise it would depend on NET).

> That could be done.  It might even meet with the approval of the
> networking maintainer, independent of this patch series.
>
> But what if somebody adds yet another networking class driver outside
> the menu?

Hmm.

Ok, how about a single (hidden) USB_HAS_NETDEV.  NETDEV_USB and
USB_ACM select USB_HAS_NETDEV.

Textual juxtaposition or simple copy+paste inside class/Kconfig should
help it get picked up.  And I'd add a comment pointing the bewildered
to the definition of usb_initdev_mask.

I'll write a patch for your inspection this evening.

Alan

Re: [PATCH 2/7 v3] initdev:kernel:USB init device discovery notification

[David VomLehn]

On Fri, Aug 07, 2009 at 06:17:51PM +0100, Alan Jenkins wrote:
> On 8/7/09, Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org> wrote:
> > On Fri, 7 Aug 2009, Alan Jenkins wrote:
> >
> >> > +/* The mask of possible USB boot devices depends on what drivers and
> >> > + * options have been configured into the kernel.  There are too many
> >> > + * USB network config options to list here, so just assume it is always
> >> > + * possible to have a USB network device.
> >> > + */
> >>
> >> That could be fixed though.  Make the "USB Network Adaptors" menu into
> >> an option.  Then you just have e.g. "CONFIG_NETDEV_USB", plus the two
> >> class devices outside the menu (CONFIG_USB_ACM and CONFIG_USB_WDM).
> 
> Oops, scratch WDM.  It doesn't actually provide a network device
> (otherwise it would depend on NET).
> 
> > That could be done.  It might even meet with the approval of the
> > networking maintainer, independent of this patch series.
> >
> > But what if somebody adds yet another networking class driver outside
> > the menu?
> 
> Hmm.
> 
> Ok, how about a single (hidden) USB_HAS_NETDEV.  NETDEV_USB and
> USB_ACM select USB_HAS_NETDEV.
> 
> Textual juxtaposition or simple copy+paste inside class/Kconfig should
> help it get picked up.  And I'd add a comment pointing the bewildered
> to the definition of usb_initdev_mask.
> 
> I'll write a patch for your inspection this evening.

I remember thinking about this and seem to recall that Alan Stern and I
tossed this idea around, but didn't act on it. Such a thing holds potential
for avoiding an unnecessary delay during boot. Whether it actually makes
things faster in a given configuration will depend on that configuration's
critical path, but I would welcome such a patch on the basis that it's
unlikely to hurt and could improve boot times in some circumstances.

> Alan
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Re: [PATCH 2/7 v3] initdev:kernel:USB init device discovery notification

[Alan Jenkins]

David VomLehn wrote:
> On Fri, Aug 07, 2009 at 06:17:51PM +0100, Alan Jenkins wrote:
>   
>> On 8/7/09, Alan Stern <stern@rowland.harvard.edu> wrote:
>>     
>>> On Fri, 7 Aug 2009, Alan Jenkins wrote:
>>>
>>>       
>>>>> +/* The mask of possible USB boot devices depends on what drivers and
>>>>> + * options have been configured into the kernel.  There are too many
>>>>> + * USB network config options to list here, so just assume it is always
>>>>> + * possible to have a USB network device.
>>>>> + */
>>>>>           
>>>> That could be fixed though.  Make the "USB Network Adaptors" menu into
>>>> an option.

> I remember thinking about this and seem to recall that Alan Stern and I
> tossed this idea around, but didn't act on it. Such a thing holds potential
> for avoiding an unnecessary delay during boot. Whether it actually makes
> things faster in a given configuration will depend on that configuration's
> critical path, but I would welcome such a patch on the basis that it's
> unlikely to hurt and could improve boot times in some circumstances.
>   

Bother, I see why this doesn't work now.  There are all the USB
*wireless* network drivers outside the menu.

Thanks anyway
Alan