linux-kernel - Re: [PATCH] drm/exynos: init vblank with real number of crtcs

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Message-id: <5434069C.3030004@samsung.com>
Date:	Wed, 08 Oct 2014 00:28:28 +0900
From:	Inki Dae <inki.dae@...sung.com>
To:	Andrzej Hajda <a.hajda@...sung.com>
Cc:	Joonyoung Shim <jy0922.shim@...sung.com>,
	Seung-Woo Kim <sw0312.kim@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	David Airlie <airlied@...ux.ie>,
	Kukjin Kim <kgene.kim@...sung.com>,
	"open list:DRM DRIVERS FOR E..." <dri-devel@...ts.freedesktop.org>,
	"moderated list:ARM/S5P EXYNOS AR..." 
	<linux-samsung-soc@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>, drake@...lessm.com,
	daniel@...ll.ch, m.szyprowski@...sung.com
Subject: Re: [PATCH] drm/exynos: init vblank with real number of crtcs


Sorry for late.

On 2014년 10월 07일 21:27, Andrzej Hajda wrote:
> Hi Inki,
> 
> Gently ping.
> 
> Andrzej
> 
> 
> On 09/19/2014 02:57 PM, Andrzej Hajda wrote:
>> Initialization of vblank with MAX_CRTC caused attempts
>> to disabling vblanks for non-existing crtcs in case
>> drm used fewer crtcs. The patch fixes it.

Nice catch~ This patch also resolves unbind issue. When exynos driver is
unbound, disable_vblank callback is called as dev->num_crtcs so if the
number of probed crtc drivers is different from the one of enabled crtc
drivers then it could attempt to disabling vblank for non-existing crtc,
which in turn, null pointer access occurs.

Thanks,
Inki Dae

>>
>> Signed-off-by: Andrzej Hajda <a.hajda@...sung.com>
>> ---
>>  drivers/gpu/drm/exynos/exynos_drm_drv.c | 18 +++++++++---------
>>  1 file changed, 9 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
>> index 9b00e4e..dc4affd 100644
>> --- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
>> +++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
>> @@ -94,10 +94,6 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
>>  	/* init kms poll for handling hpd */
>>  	drm_kms_helper_poll_init(dev);
>>  
>> -	ret = drm_vblank_init(dev, MAX_CRTC);
>> -	if (ret)
>> -		goto err_mode_config_cleanup;
>> -
>>  	/* setup possible_clones. */
>>  	exynos_drm_encoder_setup(dev);
>>  
>> @@ -106,22 +102,26 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
>>  	/* Try to bind all sub drivers. */
>>  	ret = component_bind_all(dev->dev, dev);
>>  	if (ret)
>> -		goto err_cleanup_vblank;
>> +		goto err_mode_config_cleanup;
>> +
>> +	ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
>> +	if (ret)
>> +		goto err_unbind_all;
>>  
>>  	/* Probe non kms sub drivers and virtual display driver. */
>>  	ret = exynos_drm_device_subdrv_probe(dev);
>>  	if (ret)
>> -		goto err_unbind_all;
>> +		goto err_cleanup_vblank;
>>  
>>  	/* force connectors detection */
>>  	drm_helper_hpd_irq_event(dev);
>>  
>>  	return 0;
>>  
>> -err_unbind_all:
>> -	component_unbind_all(dev->dev, dev);
>>  err_cleanup_vblank:
>>  	drm_vblank_cleanup(dev);
>> +err_unbind_all:
>> +	component_unbind_all(dev->dev, dev);
>>  err_mode_config_cleanup:
>>  	drm_mode_config_cleanup(dev);
>>  	drm_release_iommu_mapping(dev);
>> @@ -138,8 +138,8 @@ static int exynos_drm_unload(struct drm_device *dev)
>>  	exynos_drm_fbdev_fini(dev);
>>  	drm_kms_helper_poll_fini(dev);
>>  
>> -	component_unbind_all(dev->dev, dev);
>>  	drm_vblank_cleanup(dev);
>> +	component_unbind_all(dev->dev, dev);
>>  	drm_mode_config_cleanup(dev);
>>  	drm_release_iommu_mapping(dev);
>>  
>>
> 
> 

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