On Jan 3, 2008 2:47 AM, David Brownell <[EMAIL PROTECTED]> wrote: > On Wednesday 02 January 2008, Robin Getz wrote: > > From: Robin Getz <[EMAIL PROTECTED]> > > > > Allow embedded developers to turn support for USB Hubs off even if they > > have a > > full root hub. This saves the overhead (RAM and Flash size). > > ISTR that it won't save very much code though ... the Linux USB > stack structures all its enumeration logic around hubs. > > > > Allow embedded developers the capabilities of the "otg_whitelist.h" - a > > product whitelist, so USB peripherals not listed there will be rejected > > during enumeration. This is the desired operation for many embedded > > products. > > > > Signed-off-by: Robin Getz <[EMAIL PROTECTED]> > > This is probably the right thing to do. Correct me if I'm wrong, > but USB-IF recently put out some specs about "embedded hosts" which > basically boil down to saying you can adopt the same functionality > restrictions that used to be OTG-only. Which is why now there are > embedded developers who'd like this option. :) > > - Dave > >
Yes, "embedded hosts" which currently not support whole USB 2.0 spec is what Robin's patch serving for. Although in MUSB of Blackfin can support USB_OTG and we can enable this, some real embedded application just use the MUSB_HOST mode. So just enable MUSB_HOST can save some embedded space because it does not including MUSB_PERIPHERAL code. I believe some embedded SoC including embedded USB host controller also need this option open for them. Thanks -Bryan Wu > > > > > > --- > > > > drivers/usb/core/Kconfig | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > > > Index: linux-2.6.x/drivers/usb/core/Kconfig > > =================================================================== > > --- linux-2.6.x/drivers/usb/core/Kconfig (revision 4074) > > +++ linux-2.6.x/drivers/usb/core/Kconfig (working copy) > > @@ -95,8 +95,9 @@ > > > > config USB_OTG_WHITELIST > > bool "Rely on OTG Targeted Peripherals List" > > - depends on USB_OTG > > - default y > > + depends on USB_OTG || EMBEDDED > > + default y if USB_OTG > > + default n if EMBEDDED > > help > > If you say Y here, the "otg_whitelist.h" file will be used as a > > product whitelist, so USB peripherals not listed there will be > > @@ -111,7 +112,7 @@ > > > > config USB_OTG_BLACKLIST_HUB > > bool "Disable external hubs" > > - depends on USB_OTG > > + depends on USB_OTG || EMBEDDED > > help > > If you say Y here, then Linux will refuse to enumerate > > external hubs. OTG hosts are allowed to reduce hardware > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
