Re: [PATCH 2/5] drm: Compile out legacy chunks from struct drm_device

From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel.vetter@intel.com>,
	Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	DRI Development <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH 2/5] drm: Compile out legacy chunks from struct drm_device
Date: Mon, 26 Oct 2020 10:17:33 +0100	[thread overview]
Message-ID: <CAKMK7uE-DG1t5mftzE_wPfmhLvw4UTQeROUMu+fTbHWtyVUXkw@mail.gmail.com> (raw)
In-Reply-To: <f31b5607-cfd8-4ab7-3b37-a5cb36509420@suse.de>

On Mon, Oct 26, 2020 at 9:37 AM Thomas Zimmermann <tzimmermann@suse.de> wrote:
>
> Hi
>
> Am 23.10.20 um 14:28 schrieb Daniel Vetter:
> > This means some very few #ifdef in code, but it allows us to
> > enlist the compiler to make sure this stuff isn't used anymore.
> >
> > More important, only legacy drivers change drm_device (for the
> > legacy_dev_list shadow attach management), therefore this is
> > prep to allow modern drivers to have a const driver struct. Which
> > is nice, because there's a ton of function pointers in there.
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Maxime Ripard <mripard@kernel.org>
> > Cc: Thomas Zimmermann <tzimmermann@suse.de>
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>
> Review-by: Thomas Zimmermann <tzimmermann@suse.de>
>
> Sort of related: the implementation for KMS and UMS devices is more and
> more distinct from each other. Did you ever consider going for separate
> legacy helpers instead of mixing-in all these ifdefs?

I think we could split out drm_pci_legacy.c. Everything else is
already split out into separate files and made optional at the
Makefile level, it's really only in oddball places around the shared
drm_device where there's any #ifdef at all.
-Daniel

>
> Best regards
> Thomas
>
> > ---
> >  drivers/gpu/drm/drm_file.c   |  2 ++
> >  drivers/gpu/drm/drm_vblank.c | 15 ++++++++++++---
> >  include/drm/drm_drv.h        |  2 ++
> >  3 files changed, 16 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> > index 0ac4566ae3f4..b50380fa80ce 100644
> > --- a/drivers/gpu/drm/drm_file.c
> > +++ b/drivers/gpu/drm/drm_file.c
> > @@ -258,9 +258,11 @@ void drm_file_free(struct drm_file *file)
> >                 (long)old_encode_dev(file->minor->kdev->devt),
> >                 atomic_read(&dev->open_count));
> >
> > +#ifdef CONFIG_DRM_LEGACY
> >       if (drm_core_check_feature(dev, DRIVER_LEGACY) &&
> >           dev->driver->preclose)
> >               dev->driver->preclose(dev, file);
> > +#endif
> >
> >       if (drm_core_check_feature(dev, DRIVER_LEGACY))
> >               drm_legacy_lock_release(dev, file->filp);
> > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> > index ba7e741764aa..15e5ea436434 100644
> > --- a/drivers/gpu/drm/drm_vblank.c
> > +++ b/drivers/gpu/drm/drm_vblank.c
> > @@ -210,9 +210,12 @@ static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
> >
> >               if (crtc->funcs->get_vblank_counter)
> >                       return crtc->funcs->get_vblank_counter(crtc);
> > -     } else if (dev->driver->get_vblank_counter) {
> > +     }
> > +#ifdef CONFIG_DRM_LEGACY
> > +     else if (dev->driver->get_vblank_counter) {
> >               return dev->driver->get_vblank_counter(dev, pipe);
> >       }
> > +#endif
> >
> >       return drm_vblank_no_hw_counter(dev, pipe);
> >  }
> > @@ -430,9 +433,12 @@ static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
> >
> >               if (crtc->funcs->disable_vblank)
> >                       crtc->funcs->disable_vblank(crtc);
> > -     } else {
> > +     }
> > +#ifdef CONFIG_DRM_LEGACY
> > +     else {
> >               dev->driver->disable_vblank(dev, pipe);
> >       }
> > +#endif
> >  }
> >
> >  /*
> > @@ -1097,9 +1103,12 @@ static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
> >
> >               if (crtc->funcs->enable_vblank)
> >                       return crtc->funcs->enable_vblank(crtc);
> > -     } else if (dev->driver->enable_vblank) {
> > +     }
> > +#ifdef CONFIG_DRM_LEGACY
> > +     else if (dev->driver->enable_vblank) {
> >               return dev->driver->enable_vblank(dev, pipe);
> >       }
> > +#endif
> >
> >       return -EINVAL;
> >  }
> > diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> > index c6d17550efc9..7af220226a25 100644
> > --- a/include/drm/drm_drv.h
> > +++ b/include/drm/drm_drv.h
> > @@ -498,6 +498,7 @@ struct drm_driver {
> >        */
> >       const struct file_operations *fops;
> >
> > +#ifdef CONFIG_DRM_LEGACY
> >       /* Everything below here is for legacy driver, never use! */
> >       /* private: */
> >
> > @@ -512,6 +513,7 @@ struct drm_driver {
> >       int (*enable_vblank)(struct drm_device *dev, unsigned int pipe);
> >       void (*disable_vblank)(struct drm_device *dev, unsigned int pipe);
> >       int dev_priv_size;
> > +#endif
> >  };
> >
> >  void *__devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver,
> >
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Felix Imendörffer


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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