Re: [PATCH 15/16] drm/i915/display: Separate out functions to get/set VTOTAL register

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Mar 24, 2025 at 07:02:47PM +0530, Ankit Nautiyal wrote:
> Introduce helpers to get and set TRANS_VTOTAL registers.
> This will pave way to avoid reading/writing VTOTAL.Vtotal bits for
> platforms that always use VRR timing generator.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 41 +++++++++++++-------
>  1 file changed, 27 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index ae1dc32044fb..fa9c6793357e 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -2638,6 +2638,15 @@ void intel_cpu_transcoder_set_m2_n2(struct intel_crtc *crtc,
>  		      PIPE_LINK_N2(display, transcoder));
>  }
>  
> +static void intel_crtc_set_vtotal(struct intel_display *display,
> +				  enum transcoder cpu_transcoder,
> +				  u32 crtc_vdisplay, u32 crtc_vtotal)
> +{
> +	intel_de_write(display, TRANS_VTOTAL(display, cpu_transcoder),
> +		       VACTIVE(crtc_vdisplay - 1) |
> +		       VTOTAL(crtc_vtotal - 1));
> +}
> +
>  static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
>  {
>  	struct intel_display *display = to_intel_display(crtc_state);
> @@ -2702,9 +2711,8 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  		       HSYNC_START(adjusted_mode->crtc_hsync_start - 1) |
>  		       HSYNC_END(adjusted_mode->crtc_hsync_end - 1));
>  
> -	intel_de_write(display, TRANS_VTOTAL(display, cpu_transcoder),
> -		       VACTIVE(crtc_vdisplay - 1) |
> -		       VTOTAL(crtc_vtotal - 1));
> +	intel_crtc_set_vtotal(display, cpu_transcoder, crtc_vdisplay, crtc_vtotal);
> +
>  	intel_de_write(display, TRANS_VBLANK(display, cpu_transcoder),
>  		       VBLANK_START(crtc_vblank_start - 1) |
>  		       VBLANK_END(crtc_vblank_end - 1));
> @@ -2718,9 +2726,8 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  	 * bits. */
>  	if (display->platform.haswell && cpu_transcoder == TRANSCODER_EDP &&
>  	    (pipe == PIPE_B || pipe == PIPE_C))
> -		intel_de_write(display, TRANS_VTOTAL(display, pipe),
> -			       VACTIVE(crtc_vdisplay - 1) |
> -			       VTOTAL(crtc_vtotal - 1));
> +		intel_crtc_set_vtotal(display, (enum transcoder)pipe,
> +				      crtc_vdisplay, crtc_vtotal);
>  }
>  
>  static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc_state)
> @@ -2766,9 +2773,7 @@ static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc
>  	 * The double buffer latch point for TRANS_VTOTAL
>  	 * is the transcoder's undelayed vblank.
>  	 */
> -	intel_de_write(display, TRANS_VTOTAL(display, cpu_transcoder),
> -		       VACTIVE(crtc_vdisplay - 1) |
> -		       VTOTAL(crtc_vtotal - 1));
> +	intel_crtc_set_vtotal(display, cpu_transcoder, crtc_vdisplay, crtc_vtotal);

Not really a fan of special casing this that much. I think we should
probably handle it the same way we deal with the VBLANK_START vs.
TRANS_SET_CONTEXT_LATENCY.

The readount should perhaps just be handled in intel_vrr_get_config().
But I think we'll need somehting like transcoder_has_vrr() to exclude 
the DSI transcoders in a consistent way.

>  
>  	intel_vrr_set_fixed_rr_timings(crtc_state);
>  	intel_vrr_transcoder_enable(crtc_state);
> @@ -2806,6 +2811,17 @@ static bool intel_pipe_is_interlaced(const struct intel_crtc_state *crtc_state)
>  				     TRANSCONF(display, cpu_transcoder)) & TRANSCONF_INTERLACE_MASK;
>  }
>  
> +static void intel_crtc_get_vtotal(struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> +	u32 tmp = intel_de_read(display, TRANS_VTOTAL(display, cpu_transcoder));
> +
> +	adjusted_mode->crtc_vdisplay = REG_FIELD_GET(VACTIVE_MASK, tmp) + 1;
> +	adjusted_mode->crtc_vtotal = REG_FIELD_GET(VTOTAL_MASK, tmp) + 1;
> +}
> +
>  static void intel_get_transcoder_timings(struct intel_crtc *crtc,
>  					 struct intel_crtc_state *pipe_config)
>  {
> @@ -2829,9 +2845,7 @@ static void intel_get_transcoder_timings(struct intel_crtc *crtc,
>  	adjusted_mode->crtc_hsync_start = REG_FIELD_GET(HSYNC_START_MASK, tmp) + 1;
>  	adjusted_mode->crtc_hsync_end = REG_FIELD_GET(HSYNC_END_MASK, tmp) + 1;
>  
> -	tmp = intel_de_read(display, TRANS_VTOTAL(display, cpu_transcoder));
> -	adjusted_mode->crtc_vdisplay = REG_FIELD_GET(VACTIVE_MASK, tmp) + 1;
> -	adjusted_mode->crtc_vtotal = REG_FIELD_GET(VTOTAL_MASK, tmp) + 1;
> +	intel_crtc_get_vtotal(pipe_config);

>  
>  	/* FIXME TGL+ DSI transcoders have this! */
>  	if (!transcoder_is_dsi(cpu_transcoder)) {
> @@ -8168,8 +8182,7 @@ void i830_enable_pipe(struct intel_display *display, enum pipe pipe)
>  		       HBLANK_START(640 - 1) | HBLANK_END(800 - 1));
>  	intel_de_write(display, TRANS_HSYNC(display, cpu_transcoder),
>  		       HSYNC_START(656 - 1) | HSYNC_END(752 - 1));
> -	intel_de_write(display, TRANS_VTOTAL(display, cpu_transcoder),
> -		       VACTIVE(480 - 1) | VTOTAL(525 - 1));
> +	intel_crtc_set_vtotal(display, cpu_transcoder, 480, 525);


>  	intel_de_write(display, TRANS_VBLANK(display, cpu_transcoder),
>  		       VBLANK_START(480 - 1) | VBLANK_END(525 - 1));
>  	intel_de_write(display, TRANS_VSYNC(display, cpu_transcoder),
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel