From: Jani Nikula <jani.nikula@linux.intel.com>
To: Arnd Bergmann <arnd@kernel.org>,
Javier Martinez Canillas <javierm@redhat.com>
Cc: "Daniel Vetter" <daniel@ffwll.ch>,
"Kees Cook" <keescook@chromium.org>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"David Airlie" <airlied@linux.ie>,
"Arnd Bergmann" <arnd@arndb.de>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Christian König" <christian.koenig@amd.com>,
dri-devel <dri-devel@lists.freedesktop.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] [RESEND] drm: fb_helper: fix CONFIG_FB dependency
Date: Wed, 27 Oct 2021 16:06:44 +0300 [thread overview]
Message-ID: <87tuh2hb17.fsf@intel.com> (raw)
In-Reply-To: <CAK8P3a0_9U0MDLcNG8GL_ZDCGQAsB=G7DBC0k1BYB1HNQTbu4Q@mail.gmail.com>
On Wed, 27 Oct 2021, Arnd Bergmann <arnd@kernel.org> wrote:
> On Wed, Oct 27, 2021 at 2:38 PM Javier Martinez Canillas
> <javierm@redhat.com> wrote:
>> >
>> > This is something we can't easily express in Kconfig, as we can't add the
>> > dependency to a symbol that only gets selected by other drivers, which
>> > is why the dependency has to be in the user-visible symbol,
>> > in this case DRM_FBDEV_EMULATION.
>> >
>>
>> Why the dependency has to be in a user-visible symbol? What could be the
>> problem with having something like:
>>
>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>> index cea777ae7fb9..f80b404946ca 100644
>> --- a/drivers/gpu/drm/Kconfig
>> +++ b/drivers/gpu/drm/Kconfig
>> @@ -82,6 +82,7 @@ config DRM_DEBUG_SELFTEST
>> config DRM_KMS_HELPER
>> tristate
>> depends on DRM
>> + depends on (DRM_FBDEV_EMULATION && FB) || !DRM_FBDEV_EMULATION
>> help
>> CRTC helpers for KMS drivers.
>>
>> @@ -104,7 +105,6 @@ config DRM_FBDEV_EMULATION
>> bool "Enable legacy fbdev support for your modesetting driver"
>> depends on DRM
>> depends on FB
>> - select DRM_KMS_HELPER
>> select FB_CFB_FILLRECT
>> select FB_CFB_COPYAREA
>> select FB_CFB_IMAGEBLIT
>
> This fails because of all the other drivers that try to 'select DRM_KMS_HELPER'.
> Kconfig will now complain about a symbol that gets selected while its
> dependencies
> are not met.
>
> To work around that, every single driver that has 'selects DRM_KMS_HELPER' would
> now have to also list 'depends on (DRM_FBDEV_EMULATION && FB) ||
> !DRM_FBDEV_EMULATION'.
So the fix would be that nobody selects DRM_KMS_HELPER...
BR,
Jani.
>
> Arnd
--
Jani Nikula, Intel Open Source Graphics Center
next prev parent reply other threads:[~2021-10-27 13:07 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 14:28 [PATCH] [RESEND] drm: fb_helper: fix CONFIG_FB dependency Arnd Bergmann
2021-09-27 16:23 ` Kees Cook
2021-09-30 14:26 ` Daniel Vetter
2021-10-27 11:47 ` Jani Nikula
2021-10-27 12:13 ` Jani Nikula
2021-10-27 12:18 ` Arnd Bergmann
2021-10-27 12:38 ` Javier Martinez Canillas
2021-10-27 12:52 ` Arnd Bergmann
2021-10-27 12:56 ` Javier Martinez Canillas
2021-10-27 13:06 ` Jani Nikula [this message]
2021-10-27 13:25 ` Arnd Bergmann
2021-10-27 13:36 ` Javier Martinez Canillas
2021-10-27 12:55 ` Jani Nikula
2021-10-27 13:18 ` Javier Martinez Canillas
2021-10-27 13:05 ` Jani Nikula
2021-10-27 13:19 ` Javier Martinez Canillas
2021-10-28 15:24 ` Daniel Vetter
2021-10-29 12:06 ` Arnd Bergmann
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