Re: [PATCH v3 4/5] staging/android: add Doc for SW_SYNC ioctl interface

[Eric Engestrom]

On Thu, Aug 11, 2016 at 12:26:43PM -0300, Gustavo Padovan wrote:
> From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> 
> This interface is hidden from kernel headers and it is intended for use
> only for testing. So testers would have to add the ioctl information
> internally. This is to prevent misuse of this feature.
> 
> v2: take in Eric suggestions for the Documentation
> 
> Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> Reviewed-by: Eric Engestrom <eric.engestrom@xxxxxxxxxx>
> ---
>  drivers/staging/android/sw_sync.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/staging/android/sw_sync.c b/drivers/staging/android/sw_sync.c
> index 039e1f4..498ab55 100644
> --- a/drivers/staging/android/sw_sync.c
> +++ b/drivers/staging/android/sw_sync.c
> @@ -25,6 +25,36 @@
>  #define CREATE_TRACE_POINTS
>  #include "sync_trace.h"
>  
> +/*
> + * SW SYNC validation framework
> + *
> + * A sync object driver that uses a 32bit counter to coordinate
> + * synchronization.  Useful when there is no hardware primitive backing
> + * the synchronization.
> + *
> + * To start the framework just open:
> + *
> + * <debugfs>/sync/sw_sync
> + *
> + * That will create a sync timeline, all fences created under this timeline
> + * file descriptor will belong to the this timeline.
> + *
> + * The 'sw_sync' file can be opened many times as to create different
> + * timelines.
> + *
> + * Fences can be created with SW_SYNC_IOC_CREATE_FENCE ioctl with struct
> + * sw_sync_ioctl_create_fence as parameter.
> + *
> + * To increment the timeline counter, SW_SYNC_IOC_INC ioctl should be used
> + * with the increment as u32. This will update the last signaled value
> + * from the timeline and signal any fence that has seqno smaller of equal
> + * it.

You didn't fix all of it: "that has a seqno smaller or equal to it."
Missing "a" (just noticed), s/of/or/, and missing "to"  :)

Cheers,
  Eric

> + *
> + * struct sw_sync_ioctl_create_fence
> + * @value:	the seqno to initialise the fence with
> + * @name:	the name of the new sync point
> + * @fence:	return the fd of the new sync_file with the created fence
> + */
>  struct sw_sync_create_fence_data {
>  	__u32	value;
>  	char	name[32];
> @@ -35,6 +65,7 @@ struct sw_sync_create_fence_data {
>  
>  #define SW_SYNC_IOC_CREATE_FENCE	_IOWR(SW_SYNC_IOC_MAGIC, 0,\
>  		struct sw_sync_create_fence_data)
> +
>  #define SW_SYNC_IOC_INC			_IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
>  
>  static const struct fence_ops timeline_fence_ops;
> -- 
> 2.5.5
>