linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Arnd Bergmann <arnd@kernel.org>
To: Jani Nikula <jani.nikula@linux.intel.com>
Cc: "Javier Martinez Canillas" <javierm@redhat.com>,
	"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 15:25:38 +0200	[thread overview]
Message-ID: <CAK8P3a0KHwaSNqg_dz8-w6e_EJBrsQw_ti+5aErsSr+8AfV9cA@mail.gmail.com> (raw)
In-Reply-To: <87tuh2hb17.fsf@intel.com>

On Wed, Oct 27, 2021 at 3:06 PM Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Wed, 27 Oct 2021, Arnd Bergmann <arnd@kernel.org> wrote:
> > 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...

That's not going to help in this case, the way the helper functions work is that
you select them as needed, and you avoid the other dependencies. This part
works fine.

We could probably get rid of this symbol by just making it an unconditional
part of drm.ko, as almost every driver ends up using it anyway.

Arguably, this would make the end result worse, as you'd again get drm.ko
itself to link against the old framebuffer code.

What I'm not sure about is whether drivers/video/fbdev/core/fb.ko could
be split up into smaller parts so DRM_FBDEV_EMULATION could
only depend on a set of common code without the bits that are needed
for the classic fbdev drivers.

      Arnd

  reply	other threads:[~2021-10-27 13:26 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
2021-10-27 13:25               ` Arnd Bergmann [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAK8P3a0KHwaSNqg_dz8-w6e_EJBrsQw_ti+5aErsSr+8AfV9cA@mail.gmail.com \
    --to=arnd@kernel.org \
    --cc=airlied@linux.ie \
    --cc=alexander.deucher@amd.com \
    --cc=arnd@arndb.de \
    --cc=christian.koenig@amd.com \
    --cc=daniel@ffwll.ch \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=jani.nikula@linux.intel.com \
    --cc=javierm@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maarten.lankhorst@linux.intel.com \
    --cc=mripard@kernel.org \
    --cc=tzimmermann@suse.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).