[PATCH 08/16] drm: Use dev->name as fallback for dev->unique

[Emil Velikov]

Hi Daniel,

On 17 June 2016 at 08:33, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> Lots of arm drivers get this wrong and for most arm boards this is the
> right thing actually. And anyway with most loaders you want to chase
> sysfs links anyway to figure out which dri device you want.
>
> This will fix dmesg noise for rockchip and sti.
>
> Also add a fallback to driver->name for entirely virtual drivers like
> vgem.
>
> v2: Rebase on top of
>
> commit e112e593b215c394c0303dbf0534db0928e87967
> Author: Nicolas Iooss <nicolas.iooss_linux at m4x.org>
> Date:   Fri Dec 11 11:20:28 2015 +0100
>
>     drm: use dev_name as default unique name in drm_dev_alloc()
>
> and simplify a bit. Plus add a comment.
>
> Cc: Ilia Mirkin <imirkin at alum.mit.edu>
> Reported-by: Ilia Mirkin <imirkin at alum.mit.edu>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  drivers/gpu/drm/drm_drv.c   | 10 +++++-----
>  drivers/gpu/drm/drm_ioctl.c |  8 +-------
>  2 files changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 10afa2539181..ecba2511ef5a 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -523,11 +523,11 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
>                 }
>         }
>
> -       if (parent) {
> -               ret = drm_dev_set_unique(dev, dev_name(parent));
> -               if (ret)
> -                       goto err_setunique;
> -       }
> +       /* Use the parent device name as DRM device unique identifier, but fall
> +        * back to the driver name for virtual devices like vgem. */
> +       ret = drm_dev_set_unique(dev, parent ? dev_name(parent) : driver->name);
> +       if (ret)
> +               goto err_setunique;
>
>         return dev;
>
> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
> index 11eda9050215..83892b6b1e0d 100644
> --- a/drivers/gpu/drm/drm_ioctl.c
> +++ b/drivers/gpu/drm/drm_ioctl.c
> @@ -134,13 +134,7 @@ static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
>                         drm_unset_busid(dev, master);
>                         return ret;
>                 }
> -       } else {
> -               if (WARN(dev->unique == NULL,
> -                        "No drm_driver.set_busid() implementation provided by "
> -                        "%ps. Use drm_dev_set_unique() to set the unique "
> -                        "name explicitly.", dev->driver))
> -                       return -EINVAL;
> -
> +       } else if (dev->unique) {
With the drm_drv.c hunk in place this will always evaluate to true,
correct ? Hmmm strictly speaking it could be NULL since vgem/platform
devices call drm_dev_set_unique() and only sun4i checks if the
function has failed.

Is it worth dropping the check here or after (alongside) patch 10 ?

-Emil