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SubjectRe: [PATCH 3/3] mx3fb: avoid screen flash when panning with fb_set_var
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Hi, Guennadi,

Could you please review the second(2/3) patch and the third(3/3) patch
of this series?
I have addressed your comments you gave in the previous review cycle.

Thanks.

2012/6/11, Liu Ying <Ying.Liu@freescale.com>:
> Users may call FBIOPUT_VSCREENINFO ioctrl to do pan display.
> This ioctrl relies on fb_set_var() to do the job. fb_set_var()
> calls custom fb_set_par() method and then calls custom
> fb_pan_display() method. The current implementation of mx3fb
> reinitializes IPU display controller every time the custom
> fb_set_par() method is called, which makes the screen flash
> if fb_set_var() is called to do panning frequently. This patch
> compares the new var info with the cached old one to decide
> whether we really need to reinitialize IPU display controller.
> We ignore xoffset and yoffset update because it doesn't require
> to reinitialize the controller. Users may specify activate field
> of var info with FB_ACTIVATE_NOW and FB_ACTIVATE_FORCE to
> reinialize the controller by force.
>
> Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
> ---
> drivers/video/mx3fb.c | 22 +++++++++++++++++++++-
> 1 files changed, 21 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/video/mx3fb.c b/drivers/video/mx3fb.c
> index 2dd11c4..7d0aa7b 100644
> --- a/drivers/video/mx3fb.c
> +++ b/drivers/video/mx3fb.c
> @@ -721,6 +721,26 @@ static void mx3fb_dma_done(void *arg)
> complete(&mx3_fbi->flip_cmpl);
> }
>
> +static bool mx3fb_must_set_par(struct fb_info *fbi)
> +{
> + struct mx3fb_info *mx3_fbi = fbi->par;
> + struct fb_var_screeninfo old_var = mx3_fbi->cur_var;
> + struct fb_var_screeninfo new_var = fbi->var;
> +
> + if ((fbi->var.activate & FB_ACTIVATE_FORCE) &&
> + (fbi->var.activate & FB_ACTIVATE_MASK) == FB_ACTIVATE_NOW)
> + return true;
> +
> + /*
> + * Ignore xoffset and yoffset update,
> + * because pan display handles this case.
> + */
> + old_var.xoffset = new_var.xoffset;
> + old_var.yoffset = new_var.yoffset;
> +
> + return !!memcmp(&old_var, &new_var, sizeof(struct fb_var_screeninfo));
> +}
> +
> static int __set_par(struct fb_info *fbi, bool lock)
> {
> u32 mem_len, cur_xoffset, cur_yoffset;
> @@ -844,7 +864,7 @@ static int mx3fb_set_par(struct fb_info *fbi)
>
> mutex_lock(&mx3_fbi->mutex);
>
> - ret = __set_par(fbi, true);
> + ret = mx3fb_must_set_par(fbi) ? __set_par(fbi, true) : 0;
>
> mutex_unlock(&mx3_fbi->mutex);
>
> --
> 1.7.1
>
>
>


--
Best Regards,
Liu Ying


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