From 695279314f1615cdcd1ea264afd1f568a35f80df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Roberto=20de=20Souza?= <jose.souza@intel.com>
Date: Wed, 29 Sep 2021 17:14:03 -0700
Subject: drm/i915/display: Drop unnecessary frontbuffer flushes
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Git-commit: 5da579cff38d64d024c1b99bafa3347c0d5fc107
Patch-mainline: v5.16-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
This unnecessary flushes are hurting power-savings are it causes
features like PSR, FBC and DRRS to disable it self to handle
frontbuffer rendering, below some explanation of why each removed
call is not necessary.
The flush in intel_prepare_plane_fb() is not required as framebuffer
will be flipped and power-saving features do the proper flip handling
in hardware.
intel_find_initial_plane_obj() flush is not required because it is
only executed during driver load and at this point the power-saving
features are not even enabled.
And the last one intelfb_create(), is also not required as at this
point the fbdev was just allocated, userspace will draw on
it what will trigger frontbuffer invalidates and flushes later on.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210930001409.254817-3-jose.souza@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_display.c | 3 ---
drivers/gpu/drm/i915/display/intel_fbdev.c | 2 --
2 files changed, 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index a4453dd1bb51..1ce1d46dca5b 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -1711,8 +1711,6 @@ intel_find_initial_plane_obj(struct intel_crtc *crtc,
plane_state->uapi.crtc = &crtc->base;
intel_plane_copy_uapi_to_hw_state(plane_state, plane_state, crtc);
- intel_frontbuffer_flush(to_intel_frontbuffer(fb), ORIGIN_DIRTYFB);
-
atomic_or(plane->frontbuffer_bit, &to_intel_frontbuffer(fb)->bits);
}
@@ -10814,7 +10812,6 @@ intel_prepare_plane_fb(struct drm_plane *_plane,
return ret;
i915_gem_object_wait_priority(obj, 0, &attr);
- i915_gem_object_flush_frontbuffer(obj, ORIGIN_DIRTYFB);
if (!new_plane_state->uapi.fence) { /* implicit fencing */
struct dma_fence *fence;
diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
index 60d3ded27047..53484267b2a4 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -230,8 +230,6 @@ static int intelfb_create(struct drm_fb_helper *helper,
goto out_unlock;
}
- intel_frontbuffer_flush(to_frontbuffer(ifbdev), ORIGIN_DIRTYFB);
-
info = drm_fb_helper_alloc_fbi(helper);
if (IS_ERR(info)) {
drm_err(&dev_priv->drm, "Failed to allocate fb_info\n");
--
2.38.1