| Message ID | 20171211113048.3514863-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2017-12-11 at 12:30 +0100, Arnd Bergmann wrote: > One patch that was meant as a cleanup apparently did more than it intended, > allowing all combinations of legacy gadget drivers to be built into the > kernel, and leaving an empty 'choice' statement behind: > > drivers/usb/gadget/Kconfig:487:warning: choice default symbol 'USB_ETH' is not contained in the choice > > The description of commit 7a9618a22aad ("usb: gadget: allow to enable legacy > drivers without USB_ETH") was a bit cryptic, as it did not change the > behavior of USB_ETH other than allowing it to be built into the kernel > alongside other legacy gadgets, which is not a valid configuration. > > As Felipe explained in the description for commit bc49d1d17dcf ("usb: > gadget: don't couple configfs to legacy gadgets"), the configfs based > gadgets can be freely configured as loadable modules or built-in > drivers, but the legacy gadgets can only be modules if there is more > than one of them, so we require the 'choice' statement here. > > This leaves the added USB_GADGET_LEGACY menuconfig symbol in place, > but then restores the 'choice' below it, so we can enforce the > single-legacy-gadget rule as before. Hello Arnd, A discussion is ongoing about whether or not commit 7a9618a22aad should be reverted. Please drop this patch until a conclusion has been reached. Thanks, Bart.
On Mon, Dec 11, 2017 at 5:09 PM, Bart Van Assche <Bart.VanAssche@wdc.com> wrote: > On Mon, 2017-12-11 at 12:30 +0100, Arnd Bergmann wrote: >> One patch that was meant as a cleanup apparently did more than it intended, >> allowing all combinations of legacy gadget drivers to be built into the >> kernel, and leaving an empty 'choice' statement behind: >> >> drivers/usb/gadget/Kconfig:487:warning: choice default symbol 'USB_ETH' is not contained in the choice >> >> The description of commit 7a9618a22aad ("usb: gadget: allow to enable legacy >> drivers without USB_ETH") was a bit cryptic, as it did not change the >> behavior of USB_ETH other than allowing it to be built into the kernel >> alongside other legacy gadgets, which is not a valid configuration. >> >> As Felipe explained in the description for commit bc49d1d17dcf ("usb: >> gadget: don't couple configfs to legacy gadgets"), the configfs based >> gadgets can be freely configured as loadable modules or built-in >> drivers, but the legacy gadgets can only be modules if there is more >> than one of them, so we require the 'choice' statement here. >> >> This leaves the added USB_GADGET_LEGACY menuconfig symbol in place, >> but then restores the 'choice' below it, so we can enforce the >> single-legacy-gadget rule as before. > > Hello Arnd, > > A discussion is ongoing about whether or not commit 7a9618a22aad should be reverted. > Please drop this patch until a conclusion has been reached. Ok. I'll use a revert of 7a9618a22aad in my local test tree then. Reverting that is probably good, I thought about suggesting that instead, but couldn't tell whether you had a bigger plan behind that commit. Arnd
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig index 0a19a76645ad..eab61f552c19 100644 --- a/drivers/usb/gadget/Kconfig +++ b/drivers/usb/gadget/Kconfig @@ -482,34 +482,6 @@ config USB_CONFIGFS_F_TCM Both protocols can work on USB2.0 and USB3.0. UAS utilizes the USB 3.0 feature called streams support. -choice - tristate "USB Gadget precomposed configurations" - default USB_ETH - optional - help - A Linux "Gadget Driver" talks to the USB Peripheral Controller - driver through the abstract "gadget" API. Some other operating - systems call these "client" drivers, of which "class drivers" - are a subset (implementing a USB device class specification). - A gadget driver implements one or more USB functions using - the peripheral hardware. - - Gadget drivers are hardware-neutral, or "platform independent", - except that they sometimes must understand quirks or limitations - of the particular controllers they work with. For example, when - a controller doesn't support alternate configurations or provide - enough of the right types of endpoints, the gadget driver might - not be able work with that controller, or might need to implement - a less common variant of a device class protocol. - - The available choices each represent a single precomposed USB - gadget configuration. In the device model, each option contains - both the device instantiation as a child for a USB gadget - controller, and the relevant drivers for each function declared - by the device. - -endchoice - source "drivers/usb/gadget/legacy/Kconfig" endif # USB_GADGET diff --git a/drivers/usb/gadget/legacy/Kconfig b/drivers/usb/gadget/legacy/Kconfig index 9570bbeced4f..2d80a9d1d5d9 100644 --- a/drivers/usb/gadget/legacy/Kconfig +++ b/drivers/usb/gadget/legacy/Kconfig @@ -21,6 +21,32 @@ menuconfig USB_GADGET_LEGACY if USB_GADGET_LEGACY +choice + tristate "USB Gadget precomposed configurations" + default USB_ETH + optional + help + A Linux "Gadget Driver" talks to the USB Peripheral Controller + driver through the abstract "gadget" API. Some other operating + systems call these "client" drivers, of which "class drivers" + are a subset (implementing a USB device class specification). + A gadget driver implements one or more USB functions using + the peripheral hardware. + + Gadget drivers are hardware-neutral, or "platform independent", + except that they sometimes must understand quirks or limitations + of the particular controllers they work with. For example, when + a controller doesn't support alternate configurations or provide + enough of the right types of endpoints, the gadget driver might + not be able work with that controller, or might need to implement + a less common variant of a device class protocol. + + The available choices each represent a single precomposed USB + gadget configuration. In the device model, each option contains + both the device instantiation as a child for a USB gadget + controller, and the relevant drivers for each function declared + by the device. + config USB_ZERO tristate "Gadget Zero (DEVELOPMENT)" select USB_LIBCOMPOSITE @@ -499,4 +525,6 @@ config USB_G_WEBCAM Say "y" to link the driver statically, or "m" to build a dynamically linked module called "g_webcam". +endchoice + endif
One patch that was meant as a cleanup apparently did more than it intended, allowing all combinations of legacy gadget drivers to be built into the kernel, and leaving an empty 'choice' statement behind: drivers/usb/gadget/Kconfig:487:warning: choice default symbol 'USB_ETH' is not contained in the choice The description of commit 7a9618a22aad ("usb: gadget: allow to enable legacy drivers without USB_ETH") was a bit cryptic, as it did not change the behavior of USB_ETH other than allowing it to be built into the kernel alongside other legacy gadgets, which is not a valid configuration. As Felipe explained in the description for commit bc49d1d17dcf ("usb: gadget: don't couple configfs to legacy gadgets"), the configfs based gadgets can be freely configured as loadable modules or built-in drivers, but the legacy gadgets can only be modules if there is more than one of them, so we require the 'choice' statement here. This leaves the added USB_GADGET_LEGACY menuconfig symbol in place, but then restores the 'choice' below it, so we can enforce the single-legacy-gadget rule as before. Fixes: 7a9618a22aad ("usb: gadget: allow to enable legacy drivers without USB_ETH") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/usb/gadget/Kconfig | 28 ---------------------------- drivers/usb/gadget/legacy/Kconfig | 28 ++++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 28 deletions(-)