linux-kernel - [PATCH 10/10] drm/tidss: Fix atomic

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Message-Id: <20231101-tidss-probe-v1-10-45149e0f9415@ideasonboard.com>
Date:   Wed, 01 Nov 2023 11:17:47 +0200
From:   Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To:     Aradhya Bhatia <a-bhatia1@...com>,
        Devarsh Thakkar <devarsht@...com>,
        Jyri Sarha <jyri.sarha@....fi>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Subject: [PATCH 10/10] drm/tidss: Fix atomic_flush check

tidss_crtc_atomic_flush() checks if the crtc is enabled, and if not,
returns immediately as there's no reason to do any register changes.

However, the code checks for 'crtc->state->enable', which does not
reflect the actual HW state. We should instead look at the
'crtc->state->active' flag.

This causes the tidss_crtc_atomic_flush() to proceed with the flush even
if the active state is false, which then causes us to hit the
WARN_ON(!crtc->state->event) check.

Fix this by checking the active flag, and while at it, fix the related
debug print which had "active" and "needs modeset" wrong way.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
---
 drivers/gpu/drm/tidss/tidss_crtc.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/tidss/tidss_crtc.c b/drivers/gpu/drm/tidss/tidss_crtc.c
index 5e5e466f35d1..4c7009a5d643 100644
--- a/drivers/gpu/drm/tidss/tidss_crtc.c
+++ b/drivers/gpu/drm/tidss/tidss_crtc.c
@@ -169,13 +169,12 @@ static void tidss_crtc_atomic_flush(struct drm_crtc *crtc,
 	struct tidss_device *tidss = to_tidss(ddev);
 	unsigned long flags;
 
-	dev_dbg(ddev->dev,
-		"%s: %s enabled %d, needs modeset %d, event %p\n", __func__,
-		crtc->name, drm_atomic_crtc_needs_modeset(crtc->state),
-		crtc->state->enable, crtc->state->event);
+	dev_dbg(ddev->dev, "%s: %s active %d, needs modeset %d, event %p\n",
+		__func__, crtc->name, crtc->state->active,
+		drm_atomic_crtc_needs_modeset(crtc->state), crtc->state->event);
 
 	/* There is nothing to do if CRTC is not going to be enabled. */
-	if (!crtc->state->enable)
+	if (!crtc->state->active)
 		return;
 
 	/*

-- 
2.34.1