Hi, On Wed, Nov 18, 2015 at 2:27 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Wednesday 18 November 2015 12:29:27 Bin Liu wrote: >> > diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig >> > index 1f2037bbeb0d..45c83baf675d 100644 >> > --- a/drivers/usb/musb/Kconfig >> > +++ b/drivers/usb/musb/Kconfig >> > @@ -159,7 +159,7 @@ config USB_TI_CPPI_DMA >> > >> > config USB_TI_CPPI41_DMA >> > bool 'TI CPPI 4.1 (AM335x)' >> > - depends on ARCH_OMAP >> > + depends on ARCH_OMAP && DMADEVICES >> > select TI_CPPI41 >> >> I am not sure what the generic policy is, but instead of hiding >> USB_TI_CPPI41_DMA if DMADEVICES is disabled, I'd like to enable >> DMADEVICES if USB_TI_CPPI41_DMA is enabled, from user experience >> perspective. > > General policy is that you should not 'select' a symbol that is > also user-visible, as that tends to cause dependency loops and > other problems when something is enabled without the user being > aware of that. Understood. Thanks. I am okay with this patch. > > Ideally we should remove the 'select TI_CPPI41' here as well, but > what we could do instead is to make that a silent symbol and remove > the prompt so it always gets enabled implicitly when USB_TI_CPPI41_DMA > and DMADEVICES are both enabled. But what if DMADEVICES was disabled and USB_TI_CPPI41_DMA was enabled? I would think I had CPPI fully enabled for MUSB, but it didn't because TI_CPPI41 was disabled. I would think this patch is the test option so far, we might have to document somewhere that to dmaengine has to be enabled to use MUSB CPPI, but I am not sure where the best place is to document... Regards, -Bin. > > Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
