linux-kernel - [PATCH] drm/vkms: Solve bug on kms_crc

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Date:   Mon, 25 Feb 2019 11:26:06 -0300
From:   Shayenne Moura <shayenneluzmoura@...il.com>
To:     Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>,
        Haneen Mohammed <hamohammed.sa@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH] drm/vkms: Solve bug on kms_crc_cursor tests

vkms_crc_work_handle needs the value of the actual frame to
schedule the workqueue that calls periodically the vblank
handler and the destroy state functions. However, the frame
value returned from vkms_vblank_simulate is updated and
diminished in vblank_get_timestamp because it is not in a
vblank interrupt, and return an inaccurate value.

Solve this getting the actual vblank frame directly from the
vblank->count inside the `struct drm_crtc`, instead of using
the `drm_accurate_vblank_count` function.

Signed-off-by: Shayenne Moura <shayenneluzmoura@...il.com>
---
 drivers/gpu/drm/vkms/vkms_crc.c  | 4 +++-
 drivers/gpu/drm/vkms/vkms_crtc.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
index d7b409a3c0f8..09a8b00ef1f1 100644
--- a/drivers/gpu/drm/vkms/vkms_crc.c
+++ b/drivers/gpu/drm/vkms/vkms_crc.c
@@ -161,6 +161,8 @@ void vkms_crc_work_handle(struct work_struct *work)
 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 	struct vkms_device *vdev = container_of(out, struct vkms_device,
 						output);
+	unsigned int pipe = drm_crtc_index(crtc);
+	struct drm_vblank_crtc *vblank = &crtc->dev->vblank[pipe];
 	struct vkms_crc_data *primary_crc = NULL;
 	struct vkms_crc_data *cursor_crc = NULL;
 	struct drm_plane *plane;
@@ -196,7 +198,7 @@ void vkms_crc_work_handle(struct work_struct *work)
 	if (primary_crc)
 		crc32 = _vkms_get_crc(primary_crc, cursor_crc);
 
-	frame_end = drm_crtc_accurate_vblank_count(crtc);
+	frame_end = vblank->count;
 
 	/* queue_work can fail to schedule crc_work; add crc for
 	 * missing frames
diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 8a9aeb0a9ea8..9bf3268e2e92 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -10,6 +10,8 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
 						  vblank_hrtimer);
 	struct drm_crtc *crtc = &output->crtc;
 	struct vkms_crtc_state *state = to_vkms_crtc_state(crtc->state);
+	unsigned int pipe = drm_crtc_index(crtc);
+	struct drm_vblank_crtc *vblank = &crtc->dev->vblank[pipe];
 	u64 ret_overrun;
 	bool ret;
 
@@ -20,7 +22,7 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
 		DRM_ERROR("vkms failure on handling vblank");
 
 	if (state && output->crc_enabled) {
-		u64 frame = drm_crtc_accurate_vblank_count(crtc);
+		u64 frame = vblank->count;
 
 		/* update frame_start only if a queued vkms_crc_work_handle()
 		 * has read the data
-- 
2.17.1