linux-kernel - [PATCH v3 3/5] drm: xlnx: zynqmp_dpsub: Clear status register ASAP

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Date: Tue, 23 Jan 2024 18:54:00 -0800
From: Anatoliy Klymenko <anatoliy.klymenko@....com>
To: <laurent.pinchart@...asonboard.com>, <maarten.lankhorst@...ux.intel.com>,
	<mripard@...nel.org>, <tzimmermann@...e.de>, <airlied@...il.com>,
	<daniel@...ll.ch>, <michal.simek@....com>, <dri-devel@...ts.freedesktop.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v3 3/5] drm: xlnx: zynqmp_dpsub: Clear status register ASAP

Clear status register as soon as we read it.

Addressing comments from
https://lore.kernel.org/dri-devel/beb551c7-bb7e-4cd0-b166-e9aad90c4620@ideasonboard.com/

Signed-off-by: Anatoliy Klymenko <anatoliy.klymenko@....com>
---
 drivers/gpu/drm/xlnx/zynqmp_dp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index d60b7431603f..5a3335e1fffa 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -1624,6 +1624,8 @@ static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
 	u32 status, mask;
 
 	status = zynqmp_dp_read(dp, ZYNQMP_DP_INT_STATUS);
+	/* clear status register as soon as we read it */
+	zynqmp_dp_write(dp, ZYNQMP_DP_INT_STATUS, status);
 	mask = zynqmp_dp_read(dp, ZYNQMP_DP_INT_MASK);
 	if (!(status & ~mask))
 		return IRQ_NONE;
@@ -1634,8 +1636,6 @@ static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
 	if (status & ZYNQMP_DP_INT_CHBUF_OVERFLW_MASK)
 		dev_dbg_ratelimited(dp->dev, "overflow interrupt\n");
 
-	zynqmp_dp_write(dp, ZYNQMP_DP_INT_STATUS, status);
-
 	if (status & ZYNQMP_DP_INT_VBLANK_START)
 		zynqmp_dpsub_drm_handle_vblank(dp->dpsub);
 
-- 
2.25.1