Re: [PATCH v2 03/10] drm/i915/cmtg: set timings for cmtg

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

On Tue, 03 Feb 2026, Animesh Manna <animesh.manna@intel.com> wrote:
> Timing registers are separate for CMTG, read transcoder register
> and program cmtg transcoder with those values.
>
> v2:
> - Use sw state instead of reading directly from hardware. [Jani]
> - Move set_timing later after encoder enable. [Dibin]
>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> Signed-off-by: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cmtg.c     | 24 +++++++++
>  drivers/gpu/drm/i915/display/intel_cmtg.h     |  1 +
>  .../gpu/drm/i915/display/intel_cmtg_regs.h    |  7 +++
>  drivers/gpu/drm/i915/display/intel_display.c  | 51 ++++++++++++-------
>  .../drm/i915/display/intel_display_types.h    |  2 +
>  5 files changed, 67 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.c b/drivers/gpu/drm/i915/display/intel_cmtg.c
> index f5364f5a848f..4220eeece07f 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg.c
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg.c
> @@ -207,3 +207,27 @@ void intel_cmtg_set_clk_select(const struct intel_crtc_state *crtc_state)
>  	if (clk_sel_set)
>  		intel_de_rmw(display, CMTG_CLK_SEL, clk_sel_clr, clk_sel_set);
>  }
> +
> +static void intel_cmtg_set_timings(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +
> +	intel_de_write(display, TRANS_HTOTAL_CMTG(cpu_transcoder), crtc->cmtg.htotal);
> +	intel_de_write(display, TRANS_HBLANK_CMTG(cpu_transcoder), crtc->cmtg.hblank);
> +	intel_de_write(display, TRANS_HSYNC_CMTG(cpu_transcoder), crtc->cmtg.hsync);
> +	intel_de_write(display, TRANS_VTOTAL_CMTG(cpu_transcoder), crtc->cmtg.vtotal);
> +	intel_de_write(display, TRANS_VBLANK_CMTG(cpu_transcoder), crtc->cmtg.vblank);
> +	intel_de_write(display, TRANS_VSYNC_CMTG(cpu_transcoder), crtc->cmtg.vsync);
> +}
> +
> +void intel_cmtg_enable(const struct intel_crtc_state *crtc_state)
> +{
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +
> +	if (cpu_transcoder != TRANSCODER_A && cpu_transcoder != TRANSCODER_B)
> +		return;
> +
> +	intel_cmtg_set_timings(crtc_state);
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.h b/drivers/gpu/drm/i915/display/intel_cmtg.h
> index bef2426b2787..b2bb60d160fa 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg.h
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg.h
> @@ -9,6 +9,7 @@
>  struct intel_display;
>  struct intel_crtc_state;
>  
> +void intel_cmtg_enable(const struct intel_crtc_state *crtc_state);
>  void intel_cmtg_set_clk_select(const struct intel_crtc_state *crtc_state);
>  void intel_cmtg_sanitize(struct intel_display *display);
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg_regs.h b/drivers/gpu/drm/i915/display/intel_cmtg_regs.h
> index 8a767b659a23..eb24827d22f5 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg_regs.h
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg_regs.h
> @@ -20,4 +20,11 @@
>  #define TRANS_CMTG_CTL_B		_MMIO(0x6fb88)
>  #define  CMTG_ENABLE			REG_BIT(31)
>  
> +#define TRANS_HTOTAL_CMTG(id)		_MMIO(0x6F000 + (id) * 0x100)

What is id? If it's a transcoder, please use trans for the param name.

> +#define TRANS_HBLANK_CMTG(id)		_MMIO(0x6F004 + (id) * 0x100)
> +#define TRANS_HSYNC_CMTG(id)		_MMIO(0x6F008 + (id) * 0x100)
> +#define TRANS_VTOTAL_CMTG(id)		_MMIO(0x6F00C + (id) * 0x100)
> +#define TRANS_VBLANK_CMTG(id)		_MMIO(0x6F010 + (id) * 0x100)
> +#define TRANS_VSYNC_CMTG(id)		_MMIO(0x6F014 + (id) * 0x100)
> +
>  #endif /* __INTEL_CMTG_REGS_H__ */
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 564d11925af3..976af9eb3c3a 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -62,6 +62,7 @@
>  #include "intel_casf.h"
>  #include "intel_cdclk.h"
>  #include "intel_clock_gating.h"
> +#include "intel_cmtg.h"
>  #include "intel_color.h"
>  #include "intel_crt.h"
>  #include "intel_crtc.h"
> @@ -1722,6 +1723,9 @@ static void hsw_crtc_enable(struct intel_atomic_state *state,
>  			intel_crtc_wait_for_next_vblank(wa_crtc);
>  		}
>  	}
> +
> +	if (crtc->cmtg.enable)
> +		intel_cmtg_enable(new_crtc_state);
>  }
>  
>  static void ilk_crtc_disable(struct intel_atomic_state *state,
> @@ -2654,6 +2658,8 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  	const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
>  	u32 crtc_vdisplay, crtc_vtotal, crtc_vblank_start, crtc_vblank_end;
>  	int vsyncshift = 0;
> +	u32 trans_htotal_val, trans_hblank_val, trans_hsync_val;
> +	u32 trans_vtotal_val, trans_vblank_val, trans_vsync_val;
>  
>  	drm_WARN_ON(display->drm, transcoder_is_dsi(cpu_transcoder));
>  
> @@ -2702,15 +2708,15 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  			       TRANS_VSYNCSHIFT(display, cpu_transcoder),
>  			       vsyncshift);
>  
> -	intel_de_write(display, TRANS_HTOTAL(display, cpu_transcoder),
> -		       HACTIVE(adjusted_mode->crtc_hdisplay - 1) |
> -		       HTOTAL(adjusted_mode->crtc_htotal - 1));
> -	intel_de_write(display, TRANS_HBLANK(display, cpu_transcoder),
> -		       HBLANK_START(adjusted_mode->crtc_hblank_start - 1) |
> -		       HBLANK_END(adjusted_mode->crtc_hblank_end - 1));
> -	intel_de_write(display, TRANS_HSYNC(display, cpu_transcoder),
> -		       HSYNC_START(adjusted_mode->crtc_hsync_start - 1) |
> -		       HSYNC_END(adjusted_mode->crtc_hsync_end - 1));
> +	trans_htotal_val = HACTIVE(adjusted_mode->crtc_hdisplay - 1) |
> +			   HTOTAL(adjusted_mode->crtc_htotal - 1);
> +	trans_hblank_val = HBLANK_START(adjusted_mode->crtc_hblank_start - 1) |
> +			   HBLANK_END(adjusted_mode->crtc_hblank_end - 1);
> +	trans_hsync_val = HSYNC_START(adjusted_mode->crtc_hsync_start - 1) |
> +			  HSYNC_END(adjusted_mode->crtc_hsync_end - 1);
> +	intel_de_write(display, TRANS_HTOTAL(display, cpu_transcoder), trans_htotal_val);
> +	intel_de_write(display, TRANS_HBLANK(display, cpu_transcoder), trans_hblank_val);
> +	intel_de_write(display, TRANS_HSYNC(display, cpu_transcoder), trans_hsync_val);
>  
>  	/*
>  	 * For platforms that always use VRR Timing Generator, the VTOTAL.Vtotal
> @@ -2721,15 +2727,15 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  	if (intel_vrr_always_use_vrr_tg(display))
>  		crtc_vtotal = 1;
>  
> -	intel_de_write(display, TRANS_VTOTAL(display, cpu_transcoder),
> -		       VACTIVE(crtc_vdisplay - 1) |
> -		       VTOTAL(crtc_vtotal - 1));
> -	intel_de_write(display, TRANS_VBLANK(display, cpu_transcoder),
> -		       VBLANK_START(crtc_vblank_start - 1) |
> -		       VBLANK_END(crtc_vblank_end - 1));
> -	intel_de_write(display, TRANS_VSYNC(display, cpu_transcoder),
> -		       VSYNC_START(adjusted_mode->crtc_vsync_start - 1) |
> -		       VSYNC_END(adjusted_mode->crtc_vsync_end - 1));
> +	trans_vtotal_val = VACTIVE(crtc_vdisplay - 1) |
> +			   VTOTAL(crtc_vtotal - 1);
> +	trans_vblank_val = VBLANK_START(crtc_vblank_start - 1) |
> +			   VBLANK_END(crtc_vblank_end - 1);
> +	trans_vsync_val = VSYNC_START(adjusted_mode->crtc_vsync_start - 1) |
> +			  VSYNC_END(adjusted_mode->crtc_vsync_end - 1);
> +	intel_de_write(display, TRANS_VTOTAL(display, cpu_transcoder), trans_vtotal_val);
> +	intel_de_write(display, TRANS_VBLANK(display, cpu_transcoder), trans_vblank_val);
> +	intel_de_write(display, TRANS_VSYNC(display, cpu_transcoder), trans_vsync_val);
>  
>  	/* Workaround: when the EDP input selection is B, the VTOTAL_B must be
>  	 * programmed with the VTOTAL_EDP value. Same for VTOTAL_C. This is
> @@ -2753,6 +2759,15 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
>  		intel_de_write(display, DP_MIN_HBLANK_CTL(cpu_transcoder),
>  			       crtc_state->min_hblank);
>  	}
> +
> +	if (crtc->cmtg.enable) {
> +		crtc->cmtg.htotal = trans_htotal_val;
> +		crtc->cmtg.hblank = trans_hblank_val;
> +		crtc->cmtg.hsync = trans_hsync_val;
> +		crtc->cmtg.vtotal = trans_vtotal_val;
> +		crtc->cmtg.vblank = trans_vblank_val;
> +		crtc->cmtg.vsync = trans_vsync_val;
> +	}
>  }
>  
>  static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc_state)
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 1081615a14fb..defb54dd0bbe 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1572,6 +1572,8 @@ struct intel_crtc {
>  
>  	struct {
>  		bool enable;
> +		u32 htotal, hblank, hsync;
> +		u32 vtotal, vblank, vsync;

Why are these stored in the crtc?

>  	} cmtg;
>  };

-- 
Jani Nikula, Intel