[Intel-gfx] [PATCH 06/12] drm/i915: Optimize out redundant M/N updates

[Manasi Navare]

Reviewed-by: Manasi Navare <navaremanasi at chromium.org>

Manasi

On Fri, Sep 1, 2023 at 6:05 AM Ville Syrjala
<ville.syrjala at linux.intel.com> wrote:
>
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Don't perform a seamless M/N update if the values aren't actually
> changing. This avoids doing extra shenanigans during vblank evasion
> needlessly.
>
> Cc: Manasi Navare <navaremanasi at chromium.org>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 6196ef76390b..c20eaf0e7a91 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5525,7 +5525,9 @@ static void intel_crtc_check_fastset(const struct intel_crtc_state *old_crtc_sta
>         else
>                 new_crtc_state->uapi.mode_changed = false;
>
> -       if (intel_crtc_needs_modeset(new_crtc_state))
> +       if (intel_crtc_needs_modeset(new_crtc_state) ||
> +           intel_compare_link_m_n(&old_crtc_state->dp_m_n,
> +                                  &new_crtc_state->dp_m_n))
>                 new_crtc_state->update_m_n = false;
>
>         if (!intel_crtc_needs_modeset(new_crtc_state))
> --
> 2.41.0
>