From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5AFDC38A2B for ; Fri, 17 Apr 2020 17:04:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0E852220A for ; Fri, 17 Apr 2020 17:04:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727986AbgDQREv (ORCPT ); Fri, 17 Apr 2020 13:04:51 -0400 Received: from asavdk4.altibox.net ([109.247.116.15]:53714 "EHLO asavdk4.altibox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727913AbgDQREv (ORCPT ); Fri, 17 Apr 2020 13:04:51 -0400 Received: from ravnborg.org (unknown [158.248.194.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by asavdk4.altibox.net (Postfix) with ESMTPS id 47D2E804EF; Fri, 17 Apr 2020 19:04:45 +0200 (CEST) Date: Fri, 17 Apr 2020 19:04:44 +0200 From: Sam Ravnborg To: Arnd Bergmann Cc: dri-devel@lists.freedesktop.org, Jani Nikula , linux-fbdev@vger.kernel.org, marex@denx.de, dsd@laptop.org, Andrzej Hajda , airlied@linux.ie, masahiroy@kernel.org, Nicolas Pitre , Saeed Mahameed , thellstrom@vmware.com, haojian.zhuang@gmail.com, geert@linux-m68k.org, linux-renesas-soc@vger.kernel.org, Jason Gunthorpe , kieran.bingham+renesas@ideasonboard.com, linux-graphics-maintainer@vmware.com, Laurent.pinchart@ideasonboard.com, jfrederich@gmail.com, robert.jarzmik@free.fr, daniel@zonque.org Subject: Re: [PATCH 7/8] fbdev: rework backlight dependencies Message-ID: <20200417170444.GB30483@ravnborg.org> References: <20200417155553.675905-1-arnd@arndb.de> <20200417155553.675905-8-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200417155553.675905-8-arnd@arndb.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=XpTUx2N9 c=1 sm=1 tr=0 a=UWs3HLbX/2nnQ3s7vZ42gw==:117 a=UWs3HLbX/2nnQ3s7vZ42gw==:17 a=kj9zAlcOel0A:10 a=e5mUnYsNAAAA:8 a=8lmh6C7IyTPJoQKiCR8A:9 a=wtOHmKyMUfKVnwvn:21 a=CjuIK1q_8ugA:10 a=Vxmtnl_E_bksehYqCbjh:22 a=pHzHmUro8NiASowvMSCR:22 a=nt3jZW36AmriUCFCBwmW:22 Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Arnd. On Fri, Apr 17, 2020 at 05:55:52PM +0200, Arnd Bergmann wrote: > Rather than having CONFIG_FB_BACKLIGHT select CONFIG_BACKLIGHT_CLASS_DEVICE, > make any driver that needs it have a dependency on the class device > being available, to prevent circular dependencies. > > This is the same way that the backlight is already treated for the DRM > subsystem. I am not happy with the direction of this patch. It is not easy to understand that one has to enable backlight to be allowed to select a display or an fbdev driver. How about somthing like this: config BACKLIGHT_CLASS_DEVICE tristate # Will enable backlight module # Has no dependencies config BACKLIGHT bool "Backlight drivers" # Will make the backlight drivers visible - a visibility option # only if BACKLIGHT config BACKLIGHT_ATMEL_LCDC ... config BACKLIGHT_EP93XX endif All drivers outside video/backlight/ can then select BACKLIGHT_CLASS_DEVICE to get the backlight core module. Or in other words BACKLIGHT_CLASS_DEVICE is used as a sort of library symbol that gices us access to backlight functionality. I tried something like this some time ago - but it did not work out for me. But maybe I just missed something obviously in the maze of Kconfig. Loking at your patch it is obviously that the approach I suggest above would require all relevant drivers to explicit add a select BACKLIGHT_CLASS_DEVICE. But that is not a bad thing IMO. Sam > > Signed-off-by: Arnd Bergmann > --- > drivers/auxdisplay/Kconfig | 1 + > drivers/macintosh/Kconfig | 1 + > drivers/staging/fbtft/Kconfig | 1 + > drivers/staging/olpc_dcon/Kconfig | 2 +- > drivers/video/fbdev/Kconfig | 14 +++++++++++--- > 5 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig > index 48efa7a047f3..f5751b5b0e88 100644 > --- a/drivers/auxdisplay/Kconfig > +++ b/drivers/auxdisplay/Kconfig > @@ -144,6 +144,7 @@ config IMG_ASCII_LCD > config HT16K33 > tristate "Holtek Ht16K33 LED controller with keyscan" > depends on FB && OF && I2C && INPUT > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FOPS > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > diff --git a/drivers/macintosh/Kconfig b/drivers/macintosh/Kconfig > index cbd46c1c5bf7..a1c6677c7043 100644 > --- a/drivers/macintosh/Kconfig > +++ b/drivers/macintosh/Kconfig > @@ -113,6 +113,7 @@ config PMAC_MEDIABAY > config PMAC_BACKLIGHT > bool "Backlight control for LCD screens" > depends on PPC_PMAC && ADB_PMU && FB = y && (BROKEN || !PPC64) > + depends on BACKLIGHT_CLASS_DEVICE > select FB_BACKLIGHT > help > Say Y here to enable Macintosh specific extensions of the generic > diff --git a/drivers/staging/fbtft/Kconfig b/drivers/staging/fbtft/Kconfig > index dad1ddcd7b0c..c4f2f01cd798 100644 > --- a/drivers/staging/fbtft/Kconfig > +++ b/drivers/staging/fbtft/Kconfig > @@ -3,6 +3,7 @@ menuconfig FB_TFT > tristate "Support for small TFT LCD display modules" > depends on FB && SPI > depends on GPIOLIB || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > select FB_SYS_IMAGEBLIT > diff --git a/drivers/staging/olpc_dcon/Kconfig b/drivers/staging/olpc_dcon/Kconfig > index d1a0dea09ef0..a9f36538d7ab 100644 > --- a/drivers/staging/olpc_dcon/Kconfig > +++ b/drivers/staging/olpc_dcon/Kconfig > @@ -4,7 +4,7 @@ config FB_OLPC_DCON > depends on OLPC && FB > depends on I2C > depends on GPIO_CS5535 && ACPI > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > help > In order to support very low power operation, the XO laptop uses a > secondary Display CONtroller, or DCON. This secondary controller > diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig > index bcf7834dbdbf..47e1b65276f4 100644 > --- a/drivers/video/fbdev/Kconfig > +++ b/drivers/video/fbdev/Kconfig > @@ -186,7 +186,7 @@ config FB_MACMODES > config FB_BACKLIGHT > tristate > depends on FB > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > > config FB_MODE_HELPERS > bool "Enable Video Mode Handling Helpers" > @@ -275,12 +275,12 @@ config FB_ARMCLCD > tristate "ARM PrimeCell PL110 support" > depends on ARM || ARM64 || COMPILE_TEST > depends on FB && ARM_AMBA && HAS_IOMEM > + depends on BACKLIGHT_CLASS_DEVICE || !OF > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > select FB_CFB_IMAGEBLIT > select FB_MODE_HELPERS if OF > select VIDEOMODE_HELPERS if OF > - select BACKLIGHT_CLASS_DEVICE if OF > help > This framebuffer device driver is for the ARM PrimeCell PL110 > Colour LCD controller. ARM PrimeCells provide the building > @@ -861,6 +861,7 @@ config FB_ATMEL > tristate "AT91 LCD Controller support" > depends on FB && OF && HAVE_CLK && HAS_IOMEM > depends on HAVE_FB_ATMEL || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_BACKLIGHT > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > @@ -914,6 +915,7 @@ config FB_NVIDIA_DEBUG > config FB_NVIDIA_BACKLIGHT > bool "Support for backlight control" > depends on FB_NVIDIA > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_NVIDIA > default y > help > Say Y here if you want to control the backlight of your display. > @@ -961,6 +963,7 @@ config FB_RIVA_DEBUG > config FB_RIVA_BACKLIGHT > bool "Support for backlight control" > depends on FB_RIVA > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_RIVA > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1232,6 +1235,7 @@ config FB_RADEON_I2C > config FB_RADEON_BACKLIGHT > bool "Support for backlight control" > depends on FB_RADEON > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_RADEON > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1263,6 +1267,7 @@ config FB_ATY128 > config FB_ATY128_BACKLIGHT > bool "Support for backlight control" > depends on FB_ATY128 > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_ATY128 > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1312,6 +1317,7 @@ config FB_ATY_GX > > config FB_ATY_BACKLIGHT > bool "Support for backlight control" > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_ATY > depends on FB_ATY > default y > help > @@ -1855,6 +1861,7 @@ config FB_SH_MOBILE_LCDC > tristate "SuperH Mobile LCDC framebuffer support" > depends on FB && HAVE_CLK && HAS_IOMEM > depends on SUPERH || ARCH_RENESAS || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > select FB_SYS_IMAGEBLIT > @@ -2183,7 +2190,7 @@ config FB_PRE_INIT_FB > config FB_MX3 > tristate "MX3 Framebuffer support" > depends on FB && MX3_IPU > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > select FB_CFB_IMAGEBLIT > @@ -2250,6 +2257,7 @@ config FB_SSD1307 > depends on FB && I2C > depends on OF > depends on GPIOLIB || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FOPS > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > -- > 2.26.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sam Ravnborg Date: Fri, 17 Apr 2020 17:04:44 +0000 Subject: Re: [PATCH 7/8] fbdev: rework backlight dependencies Message-Id: <20200417170444.GB30483@ravnborg.org> List-Id: References: <20200417155553.675905-1-arnd@arndb.de> <20200417155553.675905-8-arnd@arndb.de> In-Reply-To: <20200417155553.675905-8-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Arnd Bergmann Cc: marex@denx.de, linux-renesas-soc@vger.kernel.org, linux-fbdev@vger.kernel.org, dsd@laptop.org, Nicolas Pitre , airlied@linux.ie, masahiroy@kernel.org, jfrederich@gmail.com, Saeed Mahameed , thellstrom@vmware.com, haojian.zhuang@gmail.com, Andrzej Hajda , kieran.bingham+renesas@ideasonboard.com, geert@linux-m68k.org, dri-devel@lists.freedesktop.org, linux-graphics-maintainer@vmware.com, robert.jarzmik@free.fr, Jason Gunthorpe , daniel@zonque.org, Laurent.pinchart@ideasonboard.com Hi Arnd. On Fri, Apr 17, 2020 at 05:55:52PM +0200, Arnd Bergmann wrote: > Rather than having CONFIG_FB_BACKLIGHT select CONFIG_BACKLIGHT_CLASS_DEVI= CE, > make any driver that needs it have a dependency on the class device > being available, to prevent circular dependencies. >=20 > This is the same way that the backlight is already treated for the DRM > subsystem. I am not happy with the direction of this patch. It is not easy to understand that one has to enable backlight to be allowed to select a display or an fbdev driver. How about somthing like this: config BACKLIGHT_CLASS_DEVICE tristate # Will enable backlight module # Has no dependencies config BACKLIGHT bool "Backlight drivers" # Will make the backlight drivers visible - a visibility option # only if BACKLIGHT config BACKLIGHT_ATMEL_LCDC ... config BACKLIGHT_EP93XX endif All drivers outside video/backlight/ can then select BACKLIGHT_CLASS_DEVICE to get the backlight core module. Or in other words BACKLIGHT_CLASS_DEVICE is used as a sort of library symbol that gices us access to backlight functionality. I tried something like this some time ago - but it did not work out for me. But maybe I just missed something obviously in the maze of Kconfig. Loking at your patch it is obviously that the approach I suggest above would require all relevant drivers to explicit add a select BACKLIGHT_CLASS_DEVICE. But that is not a bad thing IMO. Sam >=20 > Signed-off-by: Arnd Bergmann > --- > drivers/auxdisplay/Kconfig | 1 + > drivers/macintosh/Kconfig | 1 + > drivers/staging/fbtft/Kconfig | 1 + > drivers/staging/olpc_dcon/Kconfig | 2 +- > drivers/video/fbdev/Kconfig | 14 +++++++++++--- > 5 files changed, 15 insertions(+), 4 deletions(-) >=20 > diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig > index 48efa7a047f3..f5751b5b0e88 100644 > --- a/drivers/auxdisplay/Kconfig > +++ b/drivers/auxdisplay/Kconfig > @@ -144,6 +144,7 @@ config IMG_ASCII_LCD > config HT16K33 > tristate "Holtek Ht16K33 LED controller with keyscan" > depends on FB && OF && I2C && INPUT > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FOPS > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > diff --git a/drivers/macintosh/Kconfig b/drivers/macintosh/Kconfig > index cbd46c1c5bf7..a1c6677c7043 100644 > --- a/drivers/macintosh/Kconfig > +++ b/drivers/macintosh/Kconfig > @@ -113,6 +113,7 @@ config PMAC_MEDIABAY > config PMAC_BACKLIGHT > bool "Backlight control for LCD screens" > depends on PPC_PMAC && ADB_PMU && FB =3D y && (BROKEN || !PPC64) > + depends on BACKLIGHT_CLASS_DEVICE > select FB_BACKLIGHT > help > Say Y here to enable Macintosh specific extensions of the generic > diff --git a/drivers/staging/fbtft/Kconfig b/drivers/staging/fbtft/Kconfig > index dad1ddcd7b0c..c4f2f01cd798 100644 > --- a/drivers/staging/fbtft/Kconfig > +++ b/drivers/staging/fbtft/Kconfig > @@ -3,6 +3,7 @@ menuconfig FB_TFT > tristate "Support for small TFT LCD display modules" > depends on FB && SPI > depends on GPIOLIB || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > select FB_SYS_IMAGEBLIT > diff --git a/drivers/staging/olpc_dcon/Kconfig b/drivers/staging/olpc_dco= n/Kconfig > index d1a0dea09ef0..a9f36538d7ab 100644 > --- a/drivers/staging/olpc_dcon/Kconfig > +++ b/drivers/staging/olpc_dcon/Kconfig > @@ -4,7 +4,7 @@ config FB_OLPC_DCON > depends on OLPC && FB > depends on I2C > depends on GPIO_CS5535 && ACPI > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > help > In order to support very low power operation, the XO laptop uses a > secondary Display CONtroller, or DCON. This secondary controller > diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig > index bcf7834dbdbf..47e1b65276f4 100644 > --- a/drivers/video/fbdev/Kconfig > +++ b/drivers/video/fbdev/Kconfig > @@ -186,7 +186,7 @@ config FB_MACMODES > config FB_BACKLIGHT > tristate > depends on FB > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > =20 > config FB_MODE_HELPERS > bool "Enable Video Mode Handling Helpers" > @@ -275,12 +275,12 @@ config FB_ARMCLCD > tristate "ARM PrimeCell PL110 support" > depends on ARM || ARM64 || COMPILE_TEST > depends on FB && ARM_AMBA && HAS_IOMEM > + depends on BACKLIGHT_CLASS_DEVICE || !OF > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > select FB_CFB_IMAGEBLIT > select FB_MODE_HELPERS if OF > select VIDEOMODE_HELPERS if OF > - select BACKLIGHT_CLASS_DEVICE if OF > help > This framebuffer device driver is for the ARM PrimeCell PL110 > Colour LCD controller. ARM PrimeCells provide the building > @@ -861,6 +861,7 @@ config FB_ATMEL > tristate "AT91 LCD Controller support" > depends on FB && OF && HAVE_CLK && HAS_IOMEM > depends on HAVE_FB_ATMEL || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_BACKLIGHT > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > @@ -914,6 +915,7 @@ config FB_NVIDIA_DEBUG > config FB_NVIDIA_BACKLIGHT > bool "Support for backlight control" > depends on FB_NVIDIA > + depends on BACKLIGHT_CLASS_DEVICE=3Dy || BACKLIGHT_CLASS_DEVICE=FB_NVID= IA > default y > help > Say Y here if you want to control the backlight of your display. > @@ -961,6 +963,7 @@ config FB_RIVA_DEBUG > config FB_RIVA_BACKLIGHT > bool "Support for backlight control" > depends on FB_RIVA > + depends on BACKLIGHT_CLASS_DEVICE=3Dy || BACKLIGHT_CLASS_DEVICE=FB_RIVA > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1232,6 +1235,7 @@ config FB_RADEON_I2C > config FB_RADEON_BACKLIGHT > bool "Support for backlight control" > depends on FB_RADEON > + depends on BACKLIGHT_CLASS_DEVICE=3Dy || BACKLIGHT_CLASS_DEVICE=FB_RADE= ON > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1263,6 +1267,7 @@ config FB_ATY128 > config FB_ATY128_BACKLIGHT > bool "Support for backlight control" > depends on FB_ATY128 > + depends on BACKLIGHT_CLASS_DEVICE=3Dy || BACKLIGHT_CLASS_DEVICE=FB_ATY1= 28 > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1312,6 +1317,7 @@ config FB_ATY_GX > =20 > config FB_ATY_BACKLIGHT > bool "Support for backlight control" > + depends on BACKLIGHT_CLASS_DEVICE=3Dy || BACKLIGHT_CLASS_DEVICE=FB_ATY > depends on FB_ATY > default y > help > @@ -1855,6 +1861,7 @@ config FB_SH_MOBILE_LCDC > tristate "SuperH Mobile LCDC framebuffer support" > depends on FB && HAVE_CLK && HAS_IOMEM > depends on SUPERH || ARCH_RENESAS || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > select FB_SYS_IMAGEBLIT > @@ -2183,7 +2190,7 @@ config FB_PRE_INIT_FB > config FB_MX3 > tristate "MX3 Framebuffer support" > depends on FB && MX3_IPU > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > select FB_CFB_IMAGEBLIT > @@ -2250,6 +2257,7 @@ config FB_SSD1307 > depends on FB && I2C > depends on OF > depends on GPIOLIB || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FOPS > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > --=20 > 2.26.0 >=20 > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0953C2D0EF for ; 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Fri, 17 Apr 2020 19:04:45 +0200 (CEST) Date: Fri, 17 Apr 2020 19:04:44 +0200 From: Sam Ravnborg To: Arnd Bergmann Subject: Re: [PATCH 7/8] fbdev: rework backlight dependencies Message-ID: <20200417170444.GB30483@ravnborg.org> References: <20200417155553.675905-1-arnd@arndb.de> <20200417155553.675905-8-arnd@arndb.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200417155553.675905-8-arnd@arndb.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=XpTUx2N9 c=1 sm=1 tr=0 a=UWs3HLbX/2nnQ3s7vZ42gw==:117 a=UWs3HLbX/2nnQ3s7vZ42gw==:17 a=kj9zAlcOel0A:10 a=e5mUnYsNAAAA:8 a=8lmh6C7IyTPJoQKiCR8A:9 a=wtOHmKyMUfKVnwvn:21 a=CjuIK1q_8ugA:10 a=Vxmtnl_E_bksehYqCbjh:22 a=pHzHmUro8NiASowvMSCR:22 a=nt3jZW36AmriUCFCBwmW:22 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: marex@denx.de, linux-renesas-soc@vger.kernel.org, linux-fbdev@vger.kernel.org, dsd@laptop.org, Nicolas Pitre , airlied@linux.ie, masahiroy@kernel.org, jfrederich@gmail.com, Saeed Mahameed , thellstrom@vmware.com, haojian.zhuang@gmail.com, Andrzej Hajda , kieran.bingham+renesas@ideasonboard.com, geert@linux-m68k.org, dri-devel@lists.freedesktop.org, linux-graphics-maintainer@vmware.com, robert.jarzmik@free.fr, Jason Gunthorpe , daniel@zonque.org, Laurent.pinchart@ideasonboard.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Arnd. On Fri, Apr 17, 2020 at 05:55:52PM +0200, Arnd Bergmann wrote: > Rather than having CONFIG_FB_BACKLIGHT select CONFIG_BACKLIGHT_CLASS_DEVICE, > make any driver that needs it have a dependency on the class device > being available, to prevent circular dependencies. > > This is the same way that the backlight is already treated for the DRM > subsystem. I am not happy with the direction of this patch. It is not easy to understand that one has to enable backlight to be allowed to select a display or an fbdev driver. How about somthing like this: config BACKLIGHT_CLASS_DEVICE tristate # Will enable backlight module # Has no dependencies config BACKLIGHT bool "Backlight drivers" # Will make the backlight drivers visible - a visibility option # only if BACKLIGHT config BACKLIGHT_ATMEL_LCDC ... config BACKLIGHT_EP93XX endif All drivers outside video/backlight/ can then select BACKLIGHT_CLASS_DEVICE to get the backlight core module. Or in other words BACKLIGHT_CLASS_DEVICE is used as a sort of library symbol that gices us access to backlight functionality. I tried something like this some time ago - but it did not work out for me. But maybe I just missed something obviously in the maze of Kconfig. Loking at your patch it is obviously that the approach I suggest above would require all relevant drivers to explicit add a select BACKLIGHT_CLASS_DEVICE. But that is not a bad thing IMO. Sam > > Signed-off-by: Arnd Bergmann > --- > drivers/auxdisplay/Kconfig | 1 + > drivers/macintosh/Kconfig | 1 + > drivers/staging/fbtft/Kconfig | 1 + > drivers/staging/olpc_dcon/Kconfig | 2 +- > drivers/video/fbdev/Kconfig | 14 +++++++++++--- > 5 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig > index 48efa7a047f3..f5751b5b0e88 100644 > --- a/drivers/auxdisplay/Kconfig > +++ b/drivers/auxdisplay/Kconfig > @@ -144,6 +144,7 @@ config IMG_ASCII_LCD > config HT16K33 > tristate "Holtek Ht16K33 LED controller with keyscan" > depends on FB && OF && I2C && INPUT > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FOPS > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > diff --git a/drivers/macintosh/Kconfig b/drivers/macintosh/Kconfig > index cbd46c1c5bf7..a1c6677c7043 100644 > --- a/drivers/macintosh/Kconfig > +++ b/drivers/macintosh/Kconfig > @@ -113,6 +113,7 @@ config PMAC_MEDIABAY > config PMAC_BACKLIGHT > bool "Backlight control for LCD screens" > depends on PPC_PMAC && ADB_PMU && FB = y && (BROKEN || !PPC64) > + depends on BACKLIGHT_CLASS_DEVICE > select FB_BACKLIGHT > help > Say Y here to enable Macintosh specific extensions of the generic > diff --git a/drivers/staging/fbtft/Kconfig b/drivers/staging/fbtft/Kconfig > index dad1ddcd7b0c..c4f2f01cd798 100644 > --- a/drivers/staging/fbtft/Kconfig > +++ b/drivers/staging/fbtft/Kconfig > @@ -3,6 +3,7 @@ menuconfig FB_TFT > tristate "Support for small TFT LCD display modules" > depends on FB && SPI > depends on GPIOLIB || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > select FB_SYS_IMAGEBLIT > diff --git a/drivers/staging/olpc_dcon/Kconfig b/drivers/staging/olpc_dcon/Kconfig > index d1a0dea09ef0..a9f36538d7ab 100644 > --- a/drivers/staging/olpc_dcon/Kconfig > +++ b/drivers/staging/olpc_dcon/Kconfig > @@ -4,7 +4,7 @@ config FB_OLPC_DCON > depends on OLPC && FB > depends on I2C > depends on GPIO_CS5535 && ACPI > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > help > In order to support very low power operation, the XO laptop uses a > secondary Display CONtroller, or DCON. This secondary controller > diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig > index bcf7834dbdbf..47e1b65276f4 100644 > --- a/drivers/video/fbdev/Kconfig > +++ b/drivers/video/fbdev/Kconfig > @@ -186,7 +186,7 @@ config FB_MACMODES > config FB_BACKLIGHT > tristate > depends on FB > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > > config FB_MODE_HELPERS > bool "Enable Video Mode Handling Helpers" > @@ -275,12 +275,12 @@ config FB_ARMCLCD > tristate "ARM PrimeCell PL110 support" > depends on ARM || ARM64 || COMPILE_TEST > depends on FB && ARM_AMBA && HAS_IOMEM > + depends on BACKLIGHT_CLASS_DEVICE || !OF > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > select FB_CFB_IMAGEBLIT > select FB_MODE_HELPERS if OF > select VIDEOMODE_HELPERS if OF > - select BACKLIGHT_CLASS_DEVICE if OF > help > This framebuffer device driver is for the ARM PrimeCell PL110 > Colour LCD controller. ARM PrimeCells provide the building > @@ -861,6 +861,7 @@ config FB_ATMEL > tristate "AT91 LCD Controller support" > depends on FB && OF && HAVE_CLK && HAS_IOMEM > depends on HAVE_FB_ATMEL || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_BACKLIGHT > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > @@ -914,6 +915,7 @@ config FB_NVIDIA_DEBUG > config FB_NVIDIA_BACKLIGHT > bool "Support for backlight control" > depends on FB_NVIDIA > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_NVIDIA > default y > help > Say Y here if you want to control the backlight of your display. > @@ -961,6 +963,7 @@ config FB_RIVA_DEBUG > config FB_RIVA_BACKLIGHT > bool "Support for backlight control" > depends on FB_RIVA > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_RIVA > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1232,6 +1235,7 @@ config FB_RADEON_I2C > config FB_RADEON_BACKLIGHT > bool "Support for backlight control" > depends on FB_RADEON > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_RADEON > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1263,6 +1267,7 @@ config FB_ATY128 > config FB_ATY128_BACKLIGHT > bool "Support for backlight control" > depends on FB_ATY128 > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_ATY128 > default y > help > Say Y here if you want to control the backlight of your display. > @@ -1312,6 +1317,7 @@ config FB_ATY_GX > > config FB_ATY_BACKLIGHT > bool "Support for backlight control" > + depends on BACKLIGHT_CLASS_DEVICE=y || BACKLIGHT_CLASS_DEVICE=FB_ATY > depends on FB_ATY > default y > help > @@ -1855,6 +1861,7 @@ config FB_SH_MOBILE_LCDC > tristate "SuperH Mobile LCDC framebuffer support" > depends on FB && HAVE_CLK && HAS_IOMEM > depends on SUPERH || ARCH_RENESAS || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > select FB_SYS_IMAGEBLIT > @@ -2183,7 +2190,7 @@ config FB_PRE_INIT_FB > config FB_MX3 > tristate "MX3 Framebuffer support" > depends on FB && MX3_IPU > - select BACKLIGHT_CLASS_DEVICE > + depends on BACKLIGHT_CLASS_DEVICE > select FB_CFB_FILLRECT > select FB_CFB_COPYAREA > select FB_CFB_IMAGEBLIT > @@ -2250,6 +2257,7 @@ config FB_SSD1307 > depends on FB && I2C > depends on OF > depends on GPIOLIB || COMPILE_TEST > + depends on BACKLIGHT_CLASS_DEVICE > select FB_SYS_FOPS > select FB_SYS_FILLRECT > select FB_SYS_COPYAREA > -- > 2.26.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel