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Message-Id: <20230921091435.3524869-1-xji@analogixsemi.com>
Date: Thu, 21 Sep 2023 17:14:35 +0800
From: Xin Ji <xji@...logixsemi.com>
To: Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>,
Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...il.com>,
David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>
Cc: bliang@...logixsemi.com, qwen@...logixsemi.com,
hsinyi@...omium.org, Xin Ji <xji@...logixsemi.com>,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH] drm/bridge: Add 200ms delay to wait FW HPD status stable
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@...logixsemi.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
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