Re: [Intel-gfx] [PATCH] drm/i915/display/psr: Configure and Program IO buffer Wake and Fast Wake

["Souza, Jose" <jose.souza@intel.com>]

On Thu, 2021-04-01 at 20:05 +0300, Gwan-gyeong Mun wrote:
> As per b.spec 49274, the IO buffer Wake lines and Fast Wake lines can be
> calculated based on the following formula.
> 
>  IO buffer wake lines = ROUNDUP(PSR2 IO wake time / total line time in microseconds)
>  Fast wake lines = ROUNDUP(PSR2 aux transaction time / total line time in microseconds)
>  For both fields limit the minimum to 7 lines and maximum to 12 lines
>  PSR2 IO wake time = 50us, PSR2 aux transaction time = 32us.
> 
> It calculates IO buffer Wake and Fast Wake based on b.spec 49274 and
> programs it.
> 
> v2: Address Jose's review comment.
>  - Do not overwrite the values.
>  - Move calulating and validating of io_buffer_wake/fast_wake to
>     intel_psr2_config_valid() from intel_psr_compute_config()
>  - Add macros for hardcoded values.
>  - Simplify and reuse the validating the io_buffer_wake/fast_wake.
> 
> v3: Rebased
> 
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Cc: Lee Shawn C <shawn.c.lee@intel.com>
> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> ---
>  .../drm/i915/display/intel_display_types.h    |  2 +
>  drivers/gpu/drm/i915/display/intel_psr.c      | 65 +++++++++++++++----
>  drivers/gpu/drm/i915/i915_reg.h               |  8 +++
>  3 files changed, 63 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index e2e707c4dff5..79df8da9b89e 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1496,6 +1496,8 @@ struct intel_psr {
>  	u16 su_x_granularity;
>  	bool dc3co_enabled;
>  	u32 dc3co_exit_delay;
> +	u32 io_buffer_wake;
> +	u32 fast_wake;
>  	struct delayed_work dc3co_work;
>  	struct drm_dp_vsc_sdp vsc;
>  };
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 54ad5c378355..a1fff724fb67 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -531,19 +531,15 @@ static void hsw_activate_psr2(struct intel_dp *intel_dp)
>  	val |= intel_psr2_get_tp_time(intel_dp);
>  
> 
> 
> 
> 
> 
> 
> 
>  	if (DISPLAY_VER(dev_priv) >= 12) {
> -		/*
> -		 * TODO: 7 lines of IO_BUFFER_WAKE and FAST_WAKE are default
> -		 * values from BSpec. In order to setting an optimal power
> -		 * consumption, lower than 4k resoluition mode needs to decrese
> -		 * IO_BUFFER_WAKE and FAST_WAKE. And higher than 4K resolution
> -		 * mode needs to increase IO_BUFFER_WAKE and FAST_WAKE.
> -		 */
> -		val |= TGL_EDP_PSR2_BLOCK_COUNT_NUM_2;
> -		val |= TGL_EDP_PSR2_IO_BUFFER_WAKE(7);
> -		val |= TGL_EDP_PSR2_FAST_WAKE(7);
> +		if (intel_dp->psr.io_buffer_wake < 9 || intel_dp->psr.fast_wake < 9)
> +			val |= TGL_EDP_PSR2_BLOCK_COUNT_NUM_2;
> +		else
> +			val |= TGL_EDP_PSR2_BLOCK_COUNT_NUM_3;
> +		val |= TGL_EDP_PSR2_IO_BUFFER_WAKE(intel_dp->psr.io_buffer_wake);
> +		val |= TGL_EDP_PSR2_FAST_WAKE(intel_dp->psr.fast_wake);
>  	} else if (DISPLAY_VER(dev_priv) >= 9) {
> -		val |= EDP_PSR2_IO_BUFFER_WAKE(7);
> -		val |= EDP_PSR2_FAST_WAKE(7);
> +		val |= EDP_PSR2_IO_BUFFER_WAKE(intel_dp->psr.io_buffer_wake);
> +		val |= EDP_PSR2_FAST_WAKE(intel_dp->psr.fast_wake);
>  	}
>  
> 
> 
> 
> 
> 
> 
> 
>  	if (intel_dp->psr.psr2_sel_fetch_enabled) {
> @@ -724,7 +720,9 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
>  	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>  	int crtc_hdisplay = crtc_state->hw.adjusted_mode.crtc_hdisplay;
>  	int crtc_vdisplay = crtc_state->hw.adjusted_mode.crtc_vdisplay;
> +	u32 io_buffer_wake, io_buffer_wake_max, io_buffer_wake_min;
>  	int psr_max_h = 0, psr_max_v = 0, max_bpp = 0;
> +	u32 fast_wake, fast_wake_max, fast_wake_min;
>  
> 
> 
> 
> 
> 
> 
> 
>  	if (!intel_dp->psr.sink_psr2_support)
>  		return false;
> @@ -768,14 +766,26 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
>  		psr_max_h = 5120;
>  		psr_max_v = 3200;
>  		max_bpp = 30;
> +		io_buffer_wake_max = TGL_EDP_PSR2_IO_BUFFER_WAKE_MAX_LINES;
> +		io_buffer_wake_min = TGL_EDP_PSR2_IO_BUFFER_WAKE_MIN_LINES;
> +		fast_wake_max = TGL_EDP_PSR2_FAST_WAKE_MAX_LINES;
> +		fast_wake_min = TGL_EDP_PSR2_FAST_WAKE_MIN_LINES;
>  	} else if (DISPLAY_VER(dev_priv) >= 10) {
>  		psr_max_h = 4096;
>  		psr_max_v = 2304;
>  		max_bpp = 24;
> +		io_buffer_wake_max = EDP_PSR2_IO_BUFFER_WAKE_MAX_LINES;
> +		io_buffer_wake_min = EDP_PSR2_IO_BUFFER_WAKE_MIN_LINES;
> +		fast_wake_max = EDP_PSR2_FAST_WAKE_MAX_LINES;
> +		fast_wake_min = EDP_PSR2_FAST_WAKE_MIN_LINES;
>  	} else if (IS_DISPLAY_VER(dev_priv, 9)) {
>  		psr_max_h = 3640;
>  		psr_max_v = 2304;
>  		max_bpp = 24;
> +		io_buffer_wake_max = EDP_PSR2_IO_BUFFER_WAKE_MAX_LINES;
> +		io_buffer_wake_min = EDP_PSR2_IO_BUFFER_WAKE_MIN_LINES;
> +		fast_wake_max = EDP_PSR2_FAST_WAKE_MAX_LINES;
> +		fast_wake_min = EDP_PSR2_FAST_WAKE_MIN_LINES;
>  	}
>  
> 
> 
> 
> 
> 
> 
> 
>  	if (crtc_state->pipe_bpp > max_bpp) {
> @@ -785,6 +795,37 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
>  		return false;
>  	}
>  
> 
> 
> 
> 
> 
> 
> 
> +	/*
> +	 * B.Spec 49274
> +	 * IO buffer wake lines = ROUNDUP(PSR2 IO wake time / total line time in microseconds)
> +	 * Fast wake lines = ROUNDUP(PSR2 aux transaction time / total line time in microseconds)
> +	 * For both fields limit the minimum to 7 lines and maximum to 12 lines
> +	 * PSR2 IO wake time = 50us, PSR2 aux transaction time = 32us.
> +	 */
> +	io_buffer_wake = intel_usecs_to_scanlines(&crtc_state->uapi.adjusted_mode,
> +						  EDP_PSR2_IO_WAKE_TIME);
> +	fast_wake = intel_usecs_to_scanlines(&crtc_state->uapi.adjusted_mode,
> +					     EDP_PSR2_AUX_TRANSACTION_TIME);
> +
> +	if (io_buffer_wake < io_buffer_wake_min || io_buffer_wake > io_buffer_wake_max) {
> +		drm_dbg_kms(&dev_priv->drm,
> +			    "PSR condition failed: Invalid PSR2 IO Buffer Wake lines (%d)\n",
> +			    io_buffer_wake);
> +		return false;
> +	}
> +
> +	if (fast_wake < fast_wake_min || fast_wake > fast_wake_max) {
> +		drm_dbg_kms(&dev_priv->drm,
> +			    "PSR condition failed: Invalid PSR2 FAST Wake lines (%d)\n",
> +			    fast_wake);
> +		return false;
> +	}
> +
> +	intel_dp->psr.io_buffer_wake =
> +		io_buffer_wake < EDP_PSR2_IO_BUFFER_WAKE_DEFAULT ? EDP_PSR2_IO_BUFFER_WAKE_DEFAULT : io_buffer_wake;
> +	intel_dp->psr.fast_wake =
> +		fast_wake < EDP_PSR2_FAST_WAKE_DEFAULT ? EDP_PSR2_FAST_WAKE_DEFAULT : fast_wake;
> +
>  	/*
>  	 * HW sends SU blocks of size four scan lines, which means the starting
>  	 * X coordinate and Y granularity requirements will always be met. We
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index cbf7a60afe54..0fc121720364 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4568,14 +4568,22 @@ enum {
>  #define   EDP_MAX_SU_DISABLE_TIME(t)		((t) << 20)
>  #define   EDP_MAX_SU_DISABLE_TIME_MASK		(0x1f << 20)
>  #define   EDP_PSR2_IO_BUFFER_WAKE_MAX_LINES	8
> +#define   EDP_PSR2_IO_BUFFER_WAKE_MIN_LINES	5
> +#define   EDP_PSR2_IO_BUFFER_WAKE_DEFAULT	7
>  #define   EDP_PSR2_IO_BUFFER_WAKE(lines)	((EDP_PSR2_IO_BUFFER_WAKE_MAX_LINES - (lines)) << 13)
>  #define   EDP_PSR2_IO_BUFFER_WAKE_MASK		(3 << 13)
> +#define   EDP_PSR2_IO_WAKE_TIME			50

gen12+ page says that this is 42us, so I guess we will need different values for gen12+ and older.
With that fixed:

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

> +#define   TGL_EDP_PSR2_IO_BUFFER_WAKE_MAX_LINES	12
>  #define   TGL_EDP_PSR2_IO_BUFFER_WAKE_MIN_LINES	5
>  #define   TGL_EDP_PSR2_IO_BUFFER_WAKE(lines)	(((lines) - TGL_EDP_PSR2_IO_BUFFER_WAKE_MIN_LINES) << 13)
>  #define   TGL_EDP_PSR2_IO_BUFFER_WAKE_MASK	(7 << 13)
>  #define   EDP_PSR2_FAST_WAKE_MAX_LINES		8
> +#define   EDP_PSR2_FAST_WAKE_MIN_LINES		5
> +#define   EDP_PSR2_FAST_WAKE_DEFAULT		7
>  #define   EDP_PSR2_FAST_WAKE(lines)		((EDP_PSR2_FAST_WAKE_MAX_LINES - (lines)) << 11)
>  #define   EDP_PSR2_FAST_WAKE_MASK		(3 << 11)
> +#define   EDP_PSR2_AUX_TRANSACTION_TIME		32
> +#define   TGL_EDP_PSR2_FAST_WAKE_MAX_LINES	12
>  #define   TGL_EDP_PSR2_FAST_WAKE_MIN_LINES	5
>  #define   TGL_EDP_PSR2_FAST_WAKE(lines)		(((lines) - TGL_EDP_PSR2_FAST_WAKE_MIN_LINES) << 10)
>  #define   TGL_EDP_PSR2_FAST_WAKE_MASK		(7 << 10)

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