On 10/10/2025 12:10 PM, Hogander, Jouni wrote:
On Thu, 2025-10-09 at 14:30 +0530, Ankit Nautiyal wrote:
Panel Replay and PSR2 selective update require sufficient vblank
duration
to accommodate wake latencies. However, the current
wake_lines_fit_into_vblank() logic does not account for the minimum
Set Context Latency (SCL) lines.
Separate out _intel_psr_min_set_context_latency() to compute the
minimum
SCL requirement based on platform and feature usage.
The alpm_config_valid() helper is updated to pass the necessary
context for
determining whether Panel Replay or PSR2 selective update is enabled.
Signed-off-by: Ankit Nautiyal <[email protected]>
Cc: Animesh Manna <[email protected]>
Cc: Jouni Högander <[email protected]>
---
drivers/gpu/drm/i915/display/intel_psr.c | 102 ++++++++++++++-------
--
1 file changed, 61 insertions(+), 41 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
b/drivers/gpu/drm/i915/display/intel_psr.c
index 2131473cead6..212bd244beed 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1361,14 +1361,64 @@ static int
intel_psr_entry_setup_frames(struct intel_dp *intel_dp,
return entry_setup_frames;
}
+static
+int _intel_psr_min_set_context_latency(const struct intel_crtc_state
*crtc_state,
+ bool needs_panel_replay,
+ bool needs_sel_update)
+{
+ struct intel_display *display =
to_intel_display(crtc_state);
+
+ if (!crtc_state->has_psr)
+ return 0;
+
+ /* Wa_14015401596 */
+ if (intel_vrr_possible(crtc_state) &&
IS_DISPLAY_VER(display, 13, 14))
+ return 1;
+
+ /* Rest is for SRD_STATUS needed on LunarLake and onwards */
+ if (DISPLAY_VER(display) < 20)
+ return 0;
+
+ /*
+ * Comment on SRD_STATUS register in Bspec for LunarLake and
onwards:
+ *
+ * To deterministically capture the transition of the state
machine
+ * going from SRDOFFACK to IDLE, the delayed V. Blank should
be at least
+ * one line after the non-delayed V. Blank.
+ *
+ * Legacy TG: TRANS_SET_CONTEXT_LATENCY > 0
+ * VRR TG: TRANS_VRR_CTL[ VRR Guardband ] < (TRANS_VRR_VMAX[
VRR Vmax ]
+ * - TRANS_VTOTAL[ Vertical Active ])
+ *
+ * SRD_STATUS is used only by PSR1 on PantherLake.
+ * SRD_STATUS is used by PSR1 and Panel Replay DP on
LunarLake.
+ */
+
+ if (DISPLAY_VER(display) >= 30 && (needs_panel_replay ||
+ needs_sel_update))
+ return 0;
+ else if (DISPLAY_VER(display) < 30 && (needs_sel_update ||
+
intel_crtc_has_type(crtc_state,
+
INTEL_OUTPUT_EDP)))
+ return 0;
+ else
+ return 1;
+}
+
static bool wake_lines_fit_into_vblank(struct intel_dp *intel_dp,
const struct intel_crtc_state
*crtc_state,
- bool aux_less)
+ bool aux_less,
+ bool needs_sel_update,
+ bool needs_panel_replay)
{
struct intel_display *display = to_intel_display(intel_dp);
int vblank = crtc_state->hw.adjusted_mode.crtc_vblank_end -
crtc_state->hw.adjusted_mode.crtc_vblank_start;
int wake_lines;
+ int scl = _intel_psr_min_set_context_latency(crtc_state,
+
needs_sel_update,
+
needs_panel_replay);
Why can't you use crtc_state->set_context_latency?
This check wake_lines_fit_into_vblank() is called during
encoder->compute_config() path (specifically in psr_compute_config()).
At this point of time set_context_latency is not computed. It is
computed later in intel_crtc_compute_config().
There is some more discussion about it in :
https://lore.kernel.org/all/[email protected]/
Perhaps I should have mentioned this in cover-letter.
+ vblank -= scl;
if (aux_less)
wake_lines = crtc_state-
alpm_state.aux_less_wake_lines;
@@ -1390,7 +1440,9 @@ static bool wake_lines_fit_into_vblank(struct
intel_dp *intel_dp,
static bool alpm_config_valid(struct intel_dp *intel_dp,
struct intel_crtc_state *crtc_state,
- bool aux_less)
+ bool aux_less,
+ bool needs_sel_update,
+ bool needs_panel_replay)
{
struct intel_display *display = to_intel_display(intel_dp);
@@ -1400,7 +1452,8 @@ static bool alpm_config_valid(struct intel_dp
*intel_dp,
return false;
}
- if (!wake_lines_fit_into_vblank(intel_dp, crtc_state,
aux_less)) {
+ if (!wake_lines_fit_into_vblank(intel_dp, crtc_state,
aux_less,
+ needs_sel_update,
needs_panel_replay)) {
drm_dbg_kms(display->drm,
"PSR2/Panel Replay not enabled, too
short vblank time\n");
return false;
@@ -1492,7 +1545,7 @@ static bool intel_psr2_config_valid(struct
intel_dp *intel_dp,
return false;
}
- if (!alpm_config_valid(intel_dp, crtc_state, false))
+ if (!alpm_config_valid(intel_dp, crtc_state, false, true,
crtc_state->has_panel_replay))
This is a bit misleading. Someone might think intel_psr2_config_valid
could be called with crtc_state->has_panel_replay == 1. Rather use
false here.
Hmm makes sense we are checking for psr2_config_valid() only when
crtc_state->has_panel_replay is false.
Thanks for pointing this out, will fix this.
Regards,
Ankit
BR,
Jouni Högander
return false;
if (!crtc_state->enable_psr2_sel_fetch &&
@@ -1643,7 +1696,7 @@ _panel_replay_compute_config(struct intel_dp
*intel_dp,
return false;
}
- if (!alpm_config_valid(intel_dp, crtc_state, true))
+ if (!alpm_config_valid(intel_dp, crtc_state, true, false,
true))
return false;
return true;
@@ -2371,43 +2424,10 @@ void
intel_psr_trigger_frame_change_event(struct intel_dsb *dsb,
*/
int intel_psr_min_set_context_latency(const struct intel_crtc_state
*crtc_state)
{
- struct intel_display *display =
to_intel_display(crtc_state);
-
- if (!crtc_state->has_psr)
- return 0;
-
- /* Wa_14015401596 */
- if (intel_vrr_possible(crtc_state) &&
IS_DISPLAY_VER(display, 13, 14))
- return 1;
-
- /* Rest is for SRD_STATUS needed on LunarLake and onwards */
- if (DISPLAY_VER(display) < 20)
- return 0;
- /*
- * Comment on SRD_STATUS register in Bspec for LunarLake and
onwards:
- *
- * To deterministically capture the transition of the state
machine
- * going from SRDOFFACK to IDLE, the delayed V. Blank should
be at least
- * one line after the non-delayed V. Blank.
- *
- * Legacy TG: TRANS_SET_CONTEXT_LATENCY > 0
- * VRR TG: TRANS_VRR_CTL[ VRR Guardband ] < (TRANS_VRR_VMAX[
VRR Vmax ]
- * - TRANS_VTOTAL[ Vertical Active ])
- *
- * SRD_STATUS is used only by PSR1 on PantherLake.
- * SRD_STATUS is used by PSR1 and Panel Replay DP on
LunarLake.
- */
-
- if (DISPLAY_VER(display) >= 30 && (crtc_state-
has_panel_replay ||
- crtc_state-
has_sel_update))
- return 0;
- else if (DISPLAY_VER(display) < 30 && (crtc_state-
has_sel_update ||
-
intel_crtc_has_type(crtc_state,
-
INTEL_OUTPUT_EDP)))
- return 0;
- else
- return 1;
+ return _intel_psr_min_set_context_latency(crtc_state,
+ crtc_state-
has_panel_replay,
+ crtc_state-
has_sel_update);
}
static u32 man_trk_ctl_enable_bit_get(struct intel_display *display)
