From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Tue, 20 Sep 2016 09:32:51 +0100 From: Peter Griffin Subject: Re: [PATCH v9 17/19] drm/virtio: kconfig: Fix recursive dependency issue. Message-ID: <20160920083251.GB26093@griffinp-ThinkPad-X1-Carbon-2nd> References: <1473081421-16555-1-git-send-email-peter.griffin@linaro.org> <1473081421-16555-18-git-send-email-peter.griffin@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: To: Emil Velikov , Arnd Bergmann Cc: LAKML , "Linux-Kernel@Vger. Kernel. Org" , kernel@stlinux.com, vinod.koul@intel.com, patrice.chotard@st.com, dan.j.williams@intel.com, David Airlie , Gerd Hoffmann , ohad@wizery.com, bjorn.andersson@linaro.org, devicetree , linux-remoteproc@vger.kernel.org, ML dri-devel , "open list:VIRTIO GPU DRIVER" , dmaengine@vger.kernel.org, lee.jones@linaro.org List-ID: Hi Emil, On Tue, 20 Sep 2016, Emil Velikov wrote: > On 5 September 2016 at 14:16, Peter Griffin wrote: > > ST_SLIM_REMOTEPROC must select REMOTEPROC, which exposes the following > > recursive dependency. > > > From a humble skim through remoteproc, drm and a few other subsystems > I think the above is wrong. All the drivers (outside of remoteproc), > that I've seen, depend on the core component, they don't select it. I will let Bjorn comment on the remoteproc subsystem Kconfig design, and why it is like it is. For this particular SLIM_RPROC I have added it to Kconfig in keeping with all the other drivers in the remoteproc subsystem which has exposed this recursive dependency issue. For this particular kconfig symbol a quick grep reveals more drivers in the kernel using 'select', than 'depend on' git grep "select VIRTIO" | wc -l 14 git grep "depends on VIRTIO" | wc -l 10 > Furthermore most places explicitly hide the drivers from the menu if > the core component isn't enabled. Remoteproc subsystem takes a different approach, the core code is only enabled if a driver which relies on it is enabled. This IMHO makes sense, as remoteproc is not widely used (only a few particular ARM SoC's). It is true that for subsystems which rely on the core component being explicitly enabled, they often tend to hide drivers which depend on it from the menu unless it is. This also makes sense. > > Is there something that requires such a different/unusual behaviour in > remoteproc ? > I'm not sure it is that unusual...looking at config USB, it selects USB_COMMON in mfd subsystem, client drivers select MFD_CORE. I've added Arnd to this thread, as I've seen lots of Kconfig patches from him recently, maybe he has some thoughts on whether this is the correct fix or not? regards, Peter. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932570AbcITIdB (ORCPT ); Tue, 20 Sep 2016 04:33:01 -0400 Received: from mail-wm0-f47.google.com ([74.125.82.47]:35812 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932511AbcITIc4 (ORCPT ); Tue, 20 Sep 2016 04:32:56 -0400 Date: Tue, 20 Sep 2016 09:32:51 +0100 From: Peter Griffin To: Emil Velikov , Arnd Bergmann Cc: LAKML , "Linux-Kernel@Vger. Kernel. Org" , kernel@stlinux.com, vinod.koul@intel.com, patrice.chotard@st.com, dan.j.williams@intel.com, David Airlie , Gerd Hoffmann , ohad@wizery.com, bjorn.andersson@linaro.org, devicetree , linux-remoteproc@vger.kernel.org, ML dri-devel , "open list:VIRTIO GPU DRIVER" , dmaengine@vger.kernel.org, lee.jones@linaro.org Subject: Re: [PATCH v9 17/19] drm/virtio: kconfig: Fix recursive dependency issue. Message-ID: <20160920083251.GB26093@griffinp-ThinkPad-X1-Carbon-2nd> References: <1473081421-16555-1-git-send-email-peter.griffin@linaro.org> <1473081421-16555-18-git-send-email-peter.griffin@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Emil, On Tue, 20 Sep 2016, Emil Velikov wrote: > On 5 September 2016 at 14:16, Peter Griffin wrote: > > ST_SLIM_REMOTEPROC must select REMOTEPROC, which exposes the following > > recursive dependency. > > > From a humble skim through remoteproc, drm and a few other subsystems > I think the above is wrong. All the drivers (outside of remoteproc), > that I've seen, depend on the core component, they don't select it. I will let Bjorn comment on the remoteproc subsystem Kconfig design, and why it is like it is. For this particular SLIM_RPROC I have added it to Kconfig in keeping with all the other drivers in the remoteproc subsystem which has exposed this recursive dependency issue. For this particular kconfig symbol a quick grep reveals more drivers in the kernel using 'select', than 'depend on' git grep "select VIRTIO" | wc -l 14 git grep "depends on VIRTIO" | wc -l 10 > Furthermore most places explicitly hide the drivers from the menu if > the core component isn't enabled. Remoteproc subsystem takes a different approach, the core code is only enabled if a driver which relies on it is enabled. This IMHO makes sense, as remoteproc is not widely used (only a few particular ARM SoC's). It is true that for subsystems which rely on the core component being explicitly enabled, they often tend to hide drivers which depend on it from the menu unless it is. This also makes sense. > > Is there something that requires such a different/unusual behaviour in > remoteproc ? > I'm not sure it is that unusual...looking at config USB, it selects USB_COMMON in mfd subsystem, client drivers select MFD_CORE. I've added Arnd to this thread, as I've seen lots of Kconfig patches from him recently, maybe he has some thoughts on whether this is the correct fix or not? regards, Peter. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Griffin Subject: Re: [PATCH v9 17/19] drm/virtio: kconfig: Fix recursive dependency issue. Date: Tue, 20 Sep 2016 09:32:51 +0100 Message-ID: <20160920083251.GB26093@griffinp-ThinkPad-X1-Carbon-2nd> References: <1473081421-16555-1-git-send-email-peter.griffin@linaro.org> <1473081421-16555-18-git-send-email-peter.griffin@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Emil Velikov , Arnd Bergmann Cc: devicetree , kernel@stlinux.com, vinod.koul@intel.com, lee.jones@linaro.org, linux-remoteproc@vger.kernel.org, patrice.chotard@st.com, ML dri-devel , "Linux-Kernel@Vger. Kernel. Org" , David Airlie , dmaengine@vger.kernel.org, dan.j.williams@intel.com, bjorn.andersson@linaro.org, "open list:VIRTIO GPU DRIVER" , LAKML List-Id: devicetree@vger.kernel.org Hi Emil, On Tue, 20 Sep 2016, Emil Velikov wrote: > On 5 September 2016 at 14:16, Peter Griffin wrote: > > ST_SLIM_REMOTEPROC must select REMOTEPROC, which exposes the following > > recursive dependency. > > > From a humble skim through remoteproc, drm and a few other subsystems > I think the above is wrong. All the drivers (outside of remoteproc), > that I've seen, depend on the core component, they don't select it. I will let Bjorn comment on the remoteproc subsystem Kconfig design, and why it is like it is. For this particular SLIM_RPROC I have added it to Kconfig in keeping with all the other drivers in the remoteproc subsystem which has exposed this recursive dependency issue. For this particular kconfig symbol a quick grep reveals more drivers in the kernel using 'select', than 'depend on' git grep "select VIRTIO" | wc -l 14 git grep "depends on VIRTIO" | wc -l 10 > Furthermore most places explicitly hide the drivers from the menu if > the core component isn't enabled. Remoteproc subsystem takes a different approach, the core code is only enabled if a driver which relies on it is enabled. This IMHO makes sense, as remoteproc is not widely used (only a few particular ARM SoC's). It is true that for subsystems which rely on the core component being explicitly enabled, they often tend to hide drivers which depend on it from the menu unless it is. This also makes sense. > > Is there something that requires such a different/unusual behaviour in > remoteproc ? > I'm not sure it is that unusual...looking at config USB, it selects USB_COMMON in mfd subsystem, client drivers select MFD_CORE. I've added Arnd to this thread, as I've seen lots of Kconfig patches from him recently, maybe he has some thoughts on whether this is the correct fix or not? regards, Peter. From mboxrd@z Thu Jan 1 00:00:00 1970 From: peter.griffin@linaro.org (Peter Griffin) Date: Tue, 20 Sep 2016 09:32:51 +0100 Subject: [PATCH v9 17/19] drm/virtio: kconfig: Fix recursive dependency issue. In-Reply-To: References: <1473081421-16555-1-git-send-email-peter.griffin@linaro.org> <1473081421-16555-18-git-send-email-peter.griffin@linaro.org> Message-ID: <20160920083251.GB26093@griffinp-ThinkPad-X1-Carbon-2nd> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Emil, On Tue, 20 Sep 2016, Emil Velikov wrote: > On 5 September 2016 at 14:16, Peter Griffin wrote: > > ST_SLIM_REMOTEPROC must select REMOTEPROC, which exposes the following > > recursive dependency. > > > From a humble skim through remoteproc, drm and a few other subsystems > I think the above is wrong. All the drivers (outside of remoteproc), > that I've seen, depend on the core component, they don't select it. I will let Bjorn comment on the remoteproc subsystem Kconfig design, and why it is like it is. For this particular SLIM_RPROC I have added it to Kconfig in keeping with all the other drivers in the remoteproc subsystem which has exposed this recursive dependency issue. For this particular kconfig symbol a quick grep reveals more drivers in the kernel using 'select', than 'depend on' git grep "select VIRTIO" | wc -l 14 git grep "depends on VIRTIO" | wc -l 10 > Furthermore most places explicitly hide the drivers from the menu if > the core component isn't enabled. Remoteproc subsystem takes a different approach, the core code is only enabled if a driver which relies on it is enabled. This IMHO makes sense, as remoteproc is not widely used (only a few particular ARM SoC's). It is true that for subsystems which rely on the core component being explicitly enabled, they often tend to hide drivers which depend on it from the menu unless it is. This also makes sense. > > Is there something that requires such a different/unusual behaviour in > remoteproc ? > I'm not sure it is that unusual...looking at config USB, it selects USB_COMMON in mfd subsystem, client drivers select MFD_CORE. I've added Arnd to this thread, as I've seen lots of Kconfig patches from him recently, maybe he has some thoughts on whether this is the correct fix or not? regards, Peter.