Commit 29f3067a authored by Jouni Högander's avatar Jouni Högander
Browse files

drm/i915/alpm: Calculate ALPM Entry check 



ALPM Entry Check represents the number of lines needed to put the main link
to sleep and keep it in the sleep state before it can be taken out of the
SLEEP state (eDP requires the main link to be in the SLEEP state for a
minimum of 5us).

Bspec: 71477

v2: move display version check into _lnl_compute_alpm_param

Signed-off-by: default avatarJouni Högander <jouni.hogander@intel.com>
Reviewed-by: default avatarArun R Murthy <arun.r.murthy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240130111130.3298779-4-jouni.hogander@intel.com
parent 96a24945

drivers/gpu/drm/i915/display/intel_display_types.h

+3 −0
Original line number Diff line number Diff line
@@ -1716,6 +1716,9 @@ struct intel_psr { 
	struct {

		u8 io_wake_lines;

		u8 fast_wake_lines;



		/* LNL and beyond */

		u8 check_entry_lines;

	} alpm_parameters;



	ktime_t last_entry_attempt;

drivers/gpu/drm/i915/display/intel_psr.c

+29 −0
Original line number Diff line number Diff line
@@ -1126,6 +1126,30 @@ static bool _compute_psr2_sdp_prior_scanline_indication(struct intel_dp *intel_d 
	return true;

}



static bool _lnl_compute_alpm_params(struct intel_dp *intel_dp,

				     struct intel_crtc_state *crtc_state)

{

	struct drm_i915_private *i915 = dp_to_i915(intel_dp);

	int check_entry_lines;



	if (DISPLAY_VER(i915) < 20)

		return true;



	/* ALPM Entry Check = 2 + CEILING( 5us /tline ) */

	check_entry_lines = 2 +

		intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode, 5);



	if (check_entry_lines > 15)

		return false;



	if (i915->display.params.psr_safest_params)

		check_entry_lines = 15;



	intel_dp->psr.alpm_parameters.check_entry_lines = check_entry_lines;



	return true;

}



static bool _compute_alpm_params(struct intel_dp *intel_dp,

				 struct intel_crtc_state *crtc_state)

{
@@ -1140,6 +1164,8 @@ static bool _compute_alpm_params(struct intel_dp *intel_dp, 
		 * it is not enough -> use 45 us.

		 */

		fast_wake_time = 45;



		/* TODO: Check how we can use ALPM_CTL fast wake extended field */

		max_wake_lines = 12;

	} else {

		io_wake_time = 50;
@@ -1156,6 +1182,9 @@ static bool _compute_alpm_params(struct intel_dp *intel_dp, 
	    fast_wake_lines > max_wake_lines)

		return false;



	if (!_lnl_compute_alpm_params(intel_dp, crtc_state))

		return false;



	if (i915->display.params.psr_safest_params)

		io_wake_lines = fast_wake_lines = max_wake_lines;