Re: [PATCH v7 09/15] drm/i915/cmtg: Modify existing hook to disable CMTG

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

On Tue, May 26, 2026 at 07:08:05PM +0530, Animesh Manna wrote:
> From: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian@intel.com>
> 
> Earlier cmtg_disable() used to disable all instances of CMTG
> which cannot handle individual request for specific CMTG instance.
> Introduce cmtg_disable_all() which will disable all cmtg instances
> and cmtg_disable() only disable specific instance.
> 
> v2:
> - Use intel_de_rmw to simplify. [Uma]
> 
> Signed-off-by: Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian@intel.com>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cmtg.c     | 60 ++++++++++++++-----
>  drivers/gpu/drm/i915/display/intel_cmtg.h     |  1 +
>  .../gpu/drm/i915/display/intel_cmtg_regs.h    |  1 +
>  3 files changed, 47 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.c b/drivers/gpu/drm/i915/display/intel_cmtg.c
> index 34715280d65d..643e2e846d25 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg.c
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg.c
> @@ -82,6 +82,18 @@ static void intel_cmtg_dump_config(struct intel_display *display,
>  		    str_yes_no(cmtg_config->trans_b_secondary));
>  }
>  
> +static inline enum transcoder to_cmtg_transcoder(enum transcoder cpu_transcoder)
> +{
> +	switch (cpu_transcoder) {
> +	case TRANSCODER_A:
> +		return TRANSCODER_CMTG0;
> +	case TRANSCODER_B:
> +		return TRANSCODER_CMTG1;
> +	default:
> +		return INVALID_TRANSCODER;
> +	}
> +}
> +
>  static bool intel_cmtg_transcoder_is_secondary(struct intel_display *display,
>  					       enum transcoder trans)
>  {
> @@ -125,8 +137,8 @@ static bool intel_cmtg_disable_requires_modeset(struct intel_display *display,
>  	return cmtg_config->trans_a_secondary || cmtg_config->trans_b_secondary;
>  }
>  
> -static void intel_cmtg_disable(struct intel_display *display,
> -			       struct intel_cmtg_config *cmtg_config)
> +static void intel_cmtg_disable_all(struct intel_display *display,
> +				   struct intel_cmtg_config *cmtg_config)
>  {
>  	u32 clk_sel_clr = 0;
>  	u32 clk_sel_set = 0;
> @@ -157,6 +169,36 @@ static void intel_cmtg_disable(struct intel_display *display,
>  		intel_de_rmw(display, CMTG_CLK_SEL, clk_sel_clr, clk_sel_set);
>  }
>  
> +void intel_cmtg_disable(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	enum transcoder cmtg_transcoder = to_cmtg_transcoder(crtc_state->cpu_transcoder);
> +	u32 clk_sel_clr = 0;
> +
> +	if (!intel_cmtg_is_allowed(crtc_state))
> +		return;

I think we just want to track the cmtg transcoder in the crtc state,
instead of this stuff that just assumes things.

> +
> +	intel_de_rmw(display, TRANS_VRR_CTL(display, cmtg_transcoder),
> +		     VRR_CTL_VRR_ENABLE | VRR_CTL_FLIP_LINE_EN, 0);
> +
> +	intel_de_rmw(display, TRANS_DDI_FUNC_CTL2(display, cpu_transcoder),
> +		     CMTG_SECONDARY_MODE, 0);
> +
> +	intel_de_rmw(display, TRANS_CMTG_CTL(cpu_transcoder), CMTG_ENABLE, 0);
> +
> +	if (intel_de_wait_for_clear_ms(display, TRANS_CMTG_CTL(cpu_transcoder), CMTG_STATE, 50)) {
> +		drm_WARN(display->drm, 1, "CMTG: %s disable timeout\n",
> +			 transcoder_name(cpu_transcoder));
> +		return;
> +	}
> +
> +	clk_sel_clr = cpu_transcoder == TRANSCODER_A ? CMTG_CLK_SEL_A_MASK : CMTG_CLK_SEL_B_MASK;
> +	intel_de_rmw(display, CMTG_CLK_SEL, clk_sel_clr, 0);
> +
> +	drm_dbg_kms(display->drm, "CMTG: %s disabled\n", transcoder_name(cpu_transcoder));
> +}
> +
>  /*
>   * Read out CMTG configuration and, on platforms that allow disabling it without
>   * a modeset, do it.
> @@ -184,7 +226,7 @@ void intel_cmtg_sanitize(struct intel_display *display)
>  	if (intel_cmtg_disable_requires_modeset(display, &cmtg_config))
>  		return;
>  
> -	intel_cmtg_disable(display, &cmtg_config);
> +	intel_cmtg_disable_all(display, &cmtg_config);
>  }
>  
>  bool intel_cmtg_is_allowed(const struct intel_crtc_state *crtc_state)
> @@ -221,18 +263,6 @@ void intel_cmtg_set_clk_select(const struct intel_crtc_state *crtc_state)
>  		intel_de_rmw(display, CMTG_CLK_SEL, clk_sel_clr, clk_sel_set);
>  }
>  
> -static inline enum transcoder to_cmtg_transcoder(enum transcoder cpu_transcoder)
> -{
> -	switch (cpu_transcoder) {
> -	case TRANSCODER_A:
> -		return TRANSCODER_CMTG0;
> -	case TRANSCODER_B:
> -		return TRANSCODER_CMTG1;
> -	default:
> -		return INVALID_TRANSCODER;
> -	}
> -}
> -
>  void intel_cmtg_set_timings(const struct intel_crtc_state *crtc_state, bool lrr)
>  {
>  	struct intel_display *display = to_intel_display(crtc_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.h b/drivers/gpu/drm/i915/display/intel_cmtg.h
> index 12abbafa7d08..79785afccc51 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg.h
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg.h
> @@ -11,6 +11,7 @@
>  struct intel_display;
>  struct intel_crtc_state;
>  
> +void intel_cmtg_disable(const struct intel_crtc_state *crtc_state);
>  void intel_cmtg_enable_ddi(const struct intel_crtc_state *crtc_state);
>  void intel_cmtg_enable_sync(const struct intel_crtc_state *crtc_state);
>  void intel_cmtg_set_m_n(const struct intel_crtc_state *crtc_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg_regs.h b/drivers/gpu/drm/i915/display/intel_cmtg_regs.h
> index a93236bf7b75..240a02cd4a3a 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg_regs.h
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg_regs.h
> @@ -22,5 +22,6 @@
>  						    _TRANS_CMTG_CTL_A, _TRANS_CMTG_CTL_B)
>  #define  CMTG_ENABLE			REG_BIT(31)
>  #define  CMTG_SYNC_TO_PORT		REG_BIT(29)
> +#define  CMTG_STATE			REG_BIT(23)
>  
>  #endif /* __INTEL_CMTG_REGS_H__ */
> -- 
> 2.29.0

-- 
Ville Syrjälä
Intel