[PATCH 3/4] drm/omap: fix DMM driver (un)registration

[Rob Clark]

On Wed, Apr 2, 2014 at 8:37 AM, Tomi Valkeinen <tomi.valkeinen at ti.com> wrote:
> At the moment the DMM driver is never unregistered, even if it's
> registered in the omapdrm module's init function. This means we'll get
> errors when reloading the omapdrm module.
>
> Fix this by unregistering the DMM driver properly, and also change the
> module init to fail if DMM driver cannot be registered, simplifying the
> unregister path as we don't need to keep the state whether we registered
> the DMM driver or not.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> ---
>  drivers/gpu/drm/omapdrm/omap_drv.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
> index df3e66416a30..f16a07d1668d 100644
> --- a/drivers/gpu/drm/omapdrm/omap_drv.c
> +++ b/drivers/gpu/drm/omapdrm/omap_drv.c
> @@ -727,18 +727,33 @@ static struct platform_driver pdev = {
>
>  static int __init omap_drm_init(void)
>  {
> +       int r;
> +
>         DBG("init");
> -       if (platform_driver_register(&omap_dmm_driver)) {
> -               /* we can continue on without DMM.. so not fatal */
> -               dev_err(NULL, "DMM registration failed\n");
> +
> +       r = platform_driver_register(&omap_dmm_driver);

the one thing I wonder slightly about, this is making omap_dmm_driver
register fail fatal, whereas it wasn't before..

That said, I don't remember in which case the dmm driver registration
would fail.  I think registering the driver should succeed even (for
example) on omap3 without dmm/tiler device.  But I guess you've
probably tested on o3 just to make sure?  Assuming you have:

Reviewed-by: Rob Clark <robdclark at gmail.com>

> +       if (r) {
> +               pr_err("DMM driver registration failed\n");
> +               return r;
>         }
> -       return platform_driver_register(&pdev);
> +
> +       r = platform_driver_register(&pdev);
> +       if (r) {
> +               pr_err("omapdrm driver registration failed\n");
> +               platform_driver_unregister(&omap_dmm_driver);
> +               return r;
> +       }
> +
> +       return 0;
>  }
>
>  static void __exit omap_drm_fini(void)
>  {
>         DBG("fini");
> +
>         platform_driver_unregister(&pdev);
> +
> +       platform_driver_unregister(&omap_dmm_driver);
>  }
>
>  /* need late_initcall() so we load after dss_driver's are loaded */
> --
> 1.8.3.2
>