Hi Guennadi,
On 09/13/2011 11:18 PM, Guennadi Liakhovetski wrote:
> On Tue, 13 Sep 2011, Sylwester Nawrocki wrote:
>> On 09/13/2011 04:48 PM, Guennadi Liakhovetski wrote:
>>> Currently only very few drivers actually use video_device nodes, embedded
>>> in struct v4l2_subdev. Allocate these nodes dynamically for those drivers
>>> to save memory for the rest.
>>>
>>> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
>>
>> I have tested this patch with Samsung FIMC driver and with MC enabled
>> sensor driver.
>> After some hundreds of module load/unload I didn't observe anything unusual.
>> The patch seem to be safe for device node enabled subdevs. You can stick my:
>>
>> Tested-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
>>
>> if you feel so.
>
> Thanks very much for testing! However, depending on your test scenario,
> you might still not notice a problem by just loading and unloading of
> modules. It would, however, be useful to execute just one test:
>
> 1. add one line v4l2-device.c:
>
> diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c
> index a3b89f4..33226857 100644
> --- a/drivers/media/video/v4l2-device.c
> +++ b/drivers/media/video/v4l2-device.c
> @@ -195,6 +195,7 @@ EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
> static void v4l2_device_release_subdev_node(struct video_device *vdev)
> {
> struct v4l2_subdev *sd = video_get_drvdata(vdev);
> + dev_info(&vdev->dev, "%s()\n", __func__);
> sd->devnode = NULL;
> kfree(vdev);
> }
>
> 2. with this patch start and stop capture
>
> 3. check dmesg - v4l2_device_release_subdev_node() output should not be
> there yet
>
> 4. rmmod modules, then the output should be there
>
> If you could test that - that would be great!
OK, I double checked if v4l2_device_release_subdev_node() is called at the right
time, i.e. I've also checked if the streaming works in between the module unload/load.
I'd added the printk and everything behaved as expected, other than I've tracked
down a few minor bugs in the drivers in the meantime;)
I'll keep your patch applied in my development tree.
Thanks,
--
Sylwester Nawrocki
Samsung Poland R&D Center
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