[PATCH] drm: vmwgfx: Remove the legacy CRTC .prepare() helper operations

[Laurent Pinchart]

The CRTC .prepare() helper operation is legacy code, drivers should
use the .atomic_disable() operation instead.

When a CRTC is temporarily disabled prior to a mode set, the atomic
helpers call the .prepare() operation if provided instead of the
.atomic_disable() operation. In order to avoid modifying the driver's
behaviour that has an empty .prepare() implementation, we need to return
from the .atomic_disable() operation without performing any action if
the CRTC will be reenabled.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c | 15 +++------------
 drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c | 10 +++-------
 2 files changed, 6 insertions(+), 19 deletions(-)

This patch is based on top of "[PATCH 0/8] Cleanup CRTC .enable()/.disable()
cargo-cult".

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
index 854403509216..bdf6349de250 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
@@ -259,17 +259,6 @@ static void vmw_sou_crtc_mode_set_nofb(struct drm_crtc *crtc)
 }
 
 /**
- * vmw_sou_crtc_helper_prepare - Noop
- *
- * @crtc: CRTC associated with the new screen
- *
- * Prepares the CRTC for a mode set, but we don't need to do anything here.
- */
-static void vmw_sou_crtc_helper_prepare(struct drm_crtc *crtc)
-{
-}
-
-/**
  * vmw_sou_crtc_atomic_enable - Noop
  *
  * @crtc: CRTC associated with the new screen
@@ -299,6 +288,9 @@ static void vmw_sou_crtc_atomic_disable(struct drm_crtc *crtc,
 		return;
 	}
 
+	if (crtc->state->enable)
+		return;
+
 	sou = vmw_crtc_to_sou(crtc);
 	dev_priv = vmw_priv(crtc->dev);
 
@@ -574,7 +566,6 @@ drm_plane_helper_funcs vmw_sou_primary_plane_helper_funcs = {
 };
 
 static const struct drm_crtc_helper_funcs vmw_sou_crtc_helper_funcs = {
-	.prepare = vmw_sou_crtc_helper_prepare,
 	.mode_set_nofb = vmw_sou_crtc_mode_set_nofb,
 	.atomic_check = vmw_du_crtc_atomic_check,
 	.atomic_begin = vmw_du_crtc_atomic_begin,
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
index ed9404a7f457..c3bd4a012b64 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -406,12 +406,6 @@ static void vmw_stdu_crtc_mode_set_nofb(struct drm_crtc *crtc)
 			  crtc->x, crtc->y);
 }
 
-
-static void vmw_stdu_crtc_helper_prepare(struct drm_crtc *crtc)
-{
-}
-
-
 static void vmw_stdu_crtc_atomic_enable(struct drm_crtc *crtc,
 					struct drm_crtc_state *old_state)
 {
@@ -446,6 +440,9 @@ static void vmw_stdu_crtc_atomic_disable(struct drm_crtc *crtc,
 		return;
 	}
 
+	if (crtc->state->enable)
+		return;
+
 	stdu     = vmw_crtc_to_stdu(crtc);
 	dev_priv = vmw_priv(crtc->dev);
 
@@ -1416,7 +1413,6 @@ drm_plane_helper_funcs vmw_stdu_primary_plane_helper_funcs = {
 };
 
 static const struct drm_crtc_helper_funcs vmw_stdu_crtc_helper_funcs = {
-	.prepare = vmw_stdu_crtc_helper_prepare,
 	.mode_set_nofb = vmw_stdu_crtc_mode_set_nofb,
 	.atomic_check = vmw_du_crtc_atomic_check,
 	.atomic_begin = vmw_du_crtc_atomic_begin,
-- 
Regards,

Laurent Pinchart