Re: [PATCH] imx-drm: Fix probe failure

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, Aug 27, 2013 at 11:32:43PM -0300, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
> 
> Since commit b5dc0d10 (drm/imx: kill firstopen callback) the following probe
> failure is seen:
> 
> [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
> [drm] No driver support for vblank timestamp query.
> [drm] Initialized imx-drm 1.0.0 20120507 on minor 0
> imx-ldb ldb.10: adding encoder failed with -16
> imx-ldb: probe of ldb.10 failed with error -16
> imx-ipuv3 2400000.ipu: IPUv3H probed
> imx-ipuv3 2800000.ipu: IPUv3H probed
> imx-ipuv3-crtc imx-ipuv3-crtc.0: adding crtc failed with -16.
> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.0 failed with error -16
> imx-ipuv3-crtc imx-ipuv3-crtc.1: adding crtc failed with -16.
> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.1 failed with error -16
> imx-ipuv3-crtc imx-ipuv3-crtc.2: adding crtc failed with -16.
> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.2 failed with error -16
> imx-ipuv3-crtc imx-ipuv3-crtc.3: adding crtc failed with -16.
> imx-ipuv3-crtc: probe of imx-ipuv3-crtc.3 failed with error -16
> 
> 'imxdrm->references' is not keeping the references correctly, causing the probe
> to fail, so let's get rid of it.
> 
> After this patch, lvds panel is functional on a mx6qsabrelite board.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
>  drivers/staging/imx-drm/imx-drm-core.c | 25 +------------------------
>  1 file changed, 1 insertion(+), 24 deletions(-)
> 
> diff --git a/drivers/staging/imx-drm/imx-drm-core.c b/drivers/staging/imx-drm/imx-drm-core.c
> index 47c5888..98eac33 100644
> --- a/drivers/staging/imx-drm/imx-drm-core.c
> +++ b/drivers/staging/imx-drm/imx-drm-core.c
> @@ -41,7 +41,6 @@ struct imx_drm_device {
>  	struct list_head			encoder_list;
>  	struct list_head			connector_list;
>  	struct mutex				mutex;
> -	int					references;

Nack. We need the references to prevent that encoders/connectors are
(de)registered while the device is active. Simply dropping this code is
no solution.

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |