Re: [PATCH 1/3] drm/i915/dsi: Fix off by one in BXT_MIPI_TRANS_VTOTAL

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 14 Mar 2025, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> BXT_MIPI_TRANS_VTOTAL must be programmed with vtotal-1
> instead of vtotal. Make it so.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/vlv_dsi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/vlv_dsi.c b/drivers/gpu/drm/i915/display/vlv_dsi.c
> index af717df83197..661de51dfd22 100644
> --- a/drivers/gpu/drm/i915/display/vlv_dsi.c
> +++ b/drivers/gpu/drm/i915/display/vlv_dsi.c
> @@ -1060,7 +1060,7 @@ static void bxt_dsi_get_pipe_config(struct intel_encoder *encoder,
>  				              BXT_MIPI_TRANS_VACTIVE(port));
>  	adjusted_mode->crtc_vtotal =
>  				intel_de_read(display,
> -				              BXT_MIPI_TRANS_VTOTAL(port));
> +				              BXT_MIPI_TRANS_VTOTAL(port)) + 1;
>  
>  	hactive = adjusted_mode->crtc_hdisplay;
>  	hfp = intel_de_read(display, MIPI_HFP_COUNT(display, port));
> @@ -1265,7 +1265,7 @@ static void set_dsi_timings(struct intel_encoder *encoder,
>  			intel_de_write(display, BXT_MIPI_TRANS_VACTIVE(port),
>  				       adjusted_mode->crtc_vdisplay);
>  			intel_de_write(display, BXT_MIPI_TRANS_VTOTAL(port),
> -				       adjusted_mode->crtc_vtotal);
> +				       adjusted_mode->crtc_vtotal - 1);
>  		}
>  
>  		intel_de_write(display, MIPI_HACTIVE_AREA_COUNT(display, port),

-- 
Jani Nikula, Intel