Re: [PATCH v6 01/16] drm/i915/cmtg: Add intel_cmtg_is_allowed() for CMTG

[Dibin Moolakadan Subrahmanian <dibin.moolakadan.subrahmanian@intel.com>]

On 13-05-2026 22:08, Animesh Manna wrote:
> CMTG will be enabled only with DC3co, so add a separate function
> intel_cmtg_is_allowed() to check the prerequisites for enabling CMTG.
> DC3co will be enabled in a separate patch.
>
> v2:
> - Remove separate flag for DC3co from crtc_state. [Uma, Dibin]
>
> v3:
> - Do not access power domain members directly. [Jani]
>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_cmtg.c | 15 ++++++++++++++-
>   drivers/gpu/drm/i915/display/intel_cmtg.h |  4 ++++
>   2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.c b/drivers/gpu/drm/i915/display/intel_cmtg.c
> index e1fdc6fe9762..dc039bea452c 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg.c
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg.c
> @@ -4,7 +4,6 @@
>    */
>   
>   #include <linux/string_choices.h>
> -#include <linux/types.h>
>   
>   #include <drm/drm_device.h>
>   #include <drm/drm_print.h>
> @@ -16,6 +15,7 @@
>   #include "intel_display_device.h"
>   #include "intel_display_power.h"
>   #include "intel_display_regs.h"
> +#include "intel_display_types.h"
>   
>   /**
>    * DOC: Common Primary Timing Generator (CMTG)
> @@ -185,3 +185,16 @@ void intel_cmtg_sanitize(struct intel_display *display)
>   
>   	intel_cmtg_disable(display, &cmtg_config);
>   }
> +
> +bool intel_cmtg_is_allowed(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +
> +	if ((cpu_transcoder == TRANSCODER_A || cpu_transcoder == TRANSCODER_B) &&
> +	    DISPLAY_VER(display) == 35 && intel_crtc_has_type(crtc_state, INTEL_OUTPUT_EDP) &&
> +	    intel_display_power_get_current_dc_state(display) == DC_STATE_EN_DC3CO)

I would enable CMTG before setting the DC3CO state, since CMTG running is a must condition for DC3CO.
Doing it the current way creates a cyclic dependency.

> +		return true;
> +
> +	return false;
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.h b/drivers/gpu/drm/i915/display/intel_cmtg.h
> index ba62199adaa2..ed540581738f 100644
> --- a/drivers/gpu/drm/i915/display/intel_cmtg.h
> +++ b/drivers/gpu/drm/i915/display/intel_cmtg.h
> @@ -6,8 +6,12 @@
>   #ifndef __INTEL_CMTG_H__
>   #define __INTEL_CMTG_H__
>   
> +#include <linux/types.h>
> +
>   struct intel_display;
> +struct intel_crtc_state;
>   
>   void intel_cmtg_sanitize(struct intel_display *display);
> +bool intel_cmtg_is_allowed(const struct intel_crtc_state *crtc_state);
>   
>   #endif /* __INTEL_CMTG_H__ */