drm/msm/disp/dpu1: turn off vblank irqs aggressively in dpu driver

Set the flag vblank_disable_immediate = true to turn off vblank irqs
immediately as soon as drm_vblank_put is requested so that there are
no irqs triggered during idle state. This will reduce cpu wakeups
and help in power saving.

To enable vblank_disable_immediate flag the underlying KMS driver
needs to support high precision vblank timestamping and also a
reliable way of providing vblank counter which is incrementing
at the leading edge of vblank.

This patch also brings in changes to support vblank_disable_immediate
requirement in dpu driver.

Changes in v1:
 - Specify reason to add vblank timestamp support. (Rob).
 - Add changes to provide vblank counter from dpu driver.

Changes in v2:
 - Fix warn stack reported by Rob Clark with v2 patch.

Changes in v3:
 - Move back to HW frame counter (Rob).

Changes in v4:
 - Frame count mismatch was causing a DRM WARN stack spew.
   DPU HW will increment the frame count at the end of
   the sync, where as vblank will be triggered at the
   fetch_start counter which is calculated as v_total - vfp.
   This is to start fetching early for panels with low
   vbp w.r.t hw latency lines.

   Add logic to detect the line count if it falls between
   vactive and v_total then return incremented frame count value.

Signed-off-by: Kalyan Thota <kalyan_t@codeaurora.org>
Link: https://lore.kernel.org/r/1613651746-12783-1-git-send-email-kalyan_t@codeaurora.org
Signed-off-by: Rob Clark <robdclark@chromium.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
index 6f0f54588124..717178b32c68 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
@@ -256,6 +256,7 @@ static void dpu_hw_intf_get_status(
 	struct dpu_hw_blk_reg_map *c = &intf->hw;
 
 	s->is_en = DPU_REG_READ(c, INTF_TIMING_ENGINE_EN);
+	s->is_prog_fetch_en = !!(DPU_REG_READ(c, INTF_CONFIG) & BIT(31));
 	if (s->is_en) {
 		s->frame_count = DPU_REG_READ(c, INTF_FRAME_COUNT);
 		s->line_count = DPU_REG_READ(c, INTF_LINE_COUNT);