[PATCH v5 10/13] video: Only dcache flush damaged lines

[Simon Glass]

Hi Alper,

On Mon, 21 Aug 2023 at 07:51, Alper Nebi Yasak <alpernebiyasak at gmail.com> wrote:
>
> From: Alexander Graf <agraf at csgraf.de>
>
> Now that we have a damage area tells us which parts of the frame buffer
> actually need updating, let's only dcache flush those on video_sync()
> calls. With this optimization in place, frame buffer updates - especially
> on large screen such as 4k displays - speed up significantly.
>
> Signed-off-by: Alexander Graf <agraf at csgraf.de>
> Reported-by: Da Xue <da at libre.computer>
> [Alper: Use damage.xstart/yend, IS_ENABLED()]
> Co-developed-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>
> Signed-off-by: Alper Nebi Yasak <alpernebiyasak at gmail.com>
> ---
>
> Changes in v5:
> - Use xstart, ystart, xend, yend as names for damage region
> - Use IS_ENABLED() instead of CONFIG_IS_ENABLED()
>
> Changes in v2:
> - Fix dcache range; we were flushing too much before
> - Remove ifdefs
>
>  drivers/video/video-uclass.c | 41 +++++++++++++++++++++++++++++++-----
>  1 file changed, 36 insertions(+), 5 deletions(-)

This is a little strange, since flushing the whole cache will only
actually write out data that was actually written (to the display). Is
there a benefit to this patch, in terms of performance?

Regards,
Simon