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From: Xin Ji <xji@analogixsemi.com>
To: Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: qwen@analogixsemi.com, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org, hsinyi@chromium.org,
	bliang@analogixsemi.com, Xin Ji <xji@analogixsemi.com>
Subject: [PATCH] drm/bridge: Add 200ms delay to wait FW HPD status stable
Date: Thu, 21 Sep 2023 17:14:35 +0800	[thread overview]
Message-ID: <20230921091435.3524869-1-xji@analogixsemi.com> (raw)

For the none-interrupt design(sink device is panel, polling HPD
status when chip power on), anx7625 FW has more than 200ms HPD
de-bounce time in FW, for the safety to get HPD status, driver
better to wait 200ms before HPD detection after OS resume back.

Signed-off-by: Xin Ji <xji@analogixsemi.com>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 51abe42c639e..833d6d50a03d 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1464,6 +1464,9 @@ static int _anx7625_hpd_polling(struct anx7625_data *ctx,
 	if (ctx->pdata.intp_irq)
 		return 0;
 
+	/* Delay 200ms for FW HPD de-bounce */
+	usleep_range(200000, 201000);
+
 	ret = readx_poll_timeout(anx7625_read_hpd_status_p0,
 				 ctx, val,
 				 ((val & HPD_STATUS) || (val < 0)),
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Xin Ji <xji@analogixsemi.com>
To: Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: bliang@analogixsemi.com, qwen@analogixsemi.com,
	hsinyi@chromium.org, Xin Ji <xji@analogixsemi.com>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH] drm/bridge: Add 200ms delay to wait FW HPD status stable
Date: Thu, 21 Sep 2023 17:14:35 +0800	[thread overview]
Message-ID: <20230921091435.3524869-1-xji@analogixsemi.com> (raw)

For the none-interrupt design(sink device is panel, polling HPD
status when chip power on), anx7625 FW has more than 200ms HPD
de-bounce time in FW, for the safety to get HPD status, driver
better to wait 200ms before HPD detection after OS resume back.

Signed-off-by: Xin Ji <xji@analogixsemi.com>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 51abe42c639e..833d6d50a03d 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1464,6 +1464,9 @@ static int _anx7625_hpd_polling(struct anx7625_data *ctx,
 	if (ctx->pdata.intp_irq)
 		return 0;
 
+	/* Delay 200ms for FW HPD de-bounce */
+	usleep_range(200000, 201000);
+
 	ret = readx_poll_timeout(anx7625_read_hpd_status_p0,
 				 ctx, val,
 				 ((val & HPD_STATUS) || (val < 0)),
-- 
2.25.1


             reply	other threads:[~2023-09-21  9:15 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-21  9:14 Xin Ji [this message]
2023-09-21  9:14 ` [PATCH] drm/bridge: Add 200ms delay to wait FW HPD status stable Xin Ji
2023-09-21 12:09 ` Jani Nikula
2023-09-21 12:13   ` Laurent Pinchart
2023-09-21 12:13     ` Laurent Pinchart
2023-09-22  6:57     ` Xin Ji
2023-09-22  6:57       ` Xin Ji
2023-09-22  7:00   ` Xin Ji
2023-09-22  7:00     ` Xin Ji

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