Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756945AbbKRUpe (ORCPT ); Wed, 18 Nov 2015 15:45:34 -0500 Received: from mail-ig0-f178.google.com ([209.85.213.178]:33701 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755911AbbKRUpd (ORCPT ); Wed, 18 Nov 2015 15:45:33 -0500 MIME-Version: 1.0 In-Reply-To: <87y4dvgi0j.fsf@saruman.tx.rr.com> References: <4370741.70D0kgBgnp@wuerfel> <87a8qbhzvf.fsf@saruman.tx.rr.com> <87y4dvgi0j.fsf@saruman.tx.rr.com> Date: Wed, 18 Nov 2015 14:45:32 -0600 Message-ID: Subject: Re: [PATCH] usb: musb: USB_TI_CPPI41_DMA requires dmaengine support From: Bin Liu To: Felipe Balbi Cc: Arnd Bergmann , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2438 Lines: 71 On Wed, Nov 18, 2015 at 2:38 PM, Felipe Balbi wrote: > > Hi, > > Bin Liu writes: >>> Bin Liu writes: >>>> On Wed, Nov 18, 2015 at 10:18 AM, Arnd Bergmann wrote: >>>>> The CPPI-4.1 driver selects TI_CPPI41, which is a dmaengine >>>>> driver and that may not be available when CONFIG_DMADEVICES >>>>> is not set: >>>>> >>>>> warning: (USB_TI_CPPI41_DMA) selects TI_CPPI41 which has unmet direct dependencies (DMADEVICES && ARCH_OMAP) >>>>> >>>>> This adds an extra dependency to avoid generating warnings in randconfig >>>>> builds. Ideally we'd remove the 'select' statement, but that has the >>>>> potential to break defconfig files. >>>>> >>>>> Signed-off-by: Arnd Bergmann >>>>> Fixes: 411dd19c682d ("usb: musb: Kconfig: Select the DMA driver if DMA mode of MUSB is enabled") >>>>> >>>>> 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. >>> >>> that would mean "select DMADEVICES" and that's frowned upon. >> >> Currently 'select DMADEVICES' is not in there. Will adding it fix the >> dependency warning in randconfig? Sorry for the question, but I don't >> know enough about Kconfig to get the answer. > > it certainly would, but we don't like to add "select XYZ" to Kconfig > because a select bypasses the dependency tree. Let me explain: > > config A > tristate "A" > depends on B > > config B > tristate "B" > > > config C > tristate "C" > select A > > > C can select A without B being enabled. Thanks for the explanation, very clear. > > -- > balbi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/