linux-kernel - [PATCH] drm/stm: ltdc: update planes at next vblank to avoid partial refresh

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1554103457-29595-1-git-send-email-yannick.fertre@st.com>
Date:   Mon, 1 Apr 2019 09:24:17 +0200
From:   Yannick Fertré <yannick.fertre@...com>
To:     Yannick Fertre <yannick.fertre@...com>,
        Philippe Cornu <philippe.cornu@...com>,
        Vincent Abriou <vincent.abriou@...com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        <dri-devel@...ts.freedesktop.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm/stm: ltdc: update planes at next vblank to avoid partial refresh

Plane updates must be synchronized on vblank with the shadow register mechanism
to avoid partial refresh on screen.

Signed-off-by: Yannick Fertré <yannick.fertre@...com>
---
 drivers/gpu/drm/stm/ltdc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index b1741a9..c2d0800 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -426,8 +426,8 @@ static void ltdc_crtc_atomic_enable(struct drm_crtc *crtc,
 	/* Enable IRQ */
 	reg_set(ldev->regs, LTDC_IER, IER_RRIE | IER_FUIE | IER_TERRIE);
 
-	/* Immediately commit the planes */
-	reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);
+	/* Commit shadow registers = update planes at next vblank */
+	reg_set(ldev->regs, LTDC_SRCR, SRCR_VBR);
 
 	/* Enable LTDC */
 	reg_set(ldev->regs, LTDC_GCR, GCR_LTDCEN);
-- 
2.7.4