Re: dma-buf/sync_file: de-stage sync_file

From: Dave Jones
Date: Wed May 25 2016 - 22:42:19 EST

On Sat, May 21, 2016 at 05:31:53AM +0000, Linux Kernel wrote:

> dma-buf/sync_file: de-stage sync_file
> sync_file is useful to connect one or more fences to the file. The file is
> used by userspace to track fences between drivers that share DMA bufs.
> Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>


> +config SYNC_FILE
> + bool "sync_file support for fences"
> + default n
> + select ANON_INODES
> + ---help---
> + This option enables the fence framework synchronization to export
> + sync_files to userspace that can represent one or more fences.

For such a generic sounding CONFIG_ item, this is one of the more obtuse descriptions
in a kconfig we've had in a while, and the commit message doesn't give any more
clues as to why anyone might want to enable this.

I'm guessing this is some graphics thing given that Daniel reviewed it.
>From skimming the other commits, it seems to be some Android thing ?
Are there depends missing perhaps that might make this more obvious ?

Could you elaborate in the help text why someone might want to enable this ?
As is, it's just a bunch of words with no context for anyone who isn't
close to whatever domain this came from.