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 v2] drm/bridge: Add 200ms delay to wait FW HPD status stable
Date: Fri, 22 Sep 2023 17:34:49 +0800 [thread overview]
Message-ID: <20230922093450.3574349-1-xji@analogixsemi.com> (raw)
For the no-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..8f740154707d 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 */
+ msleep(200);
+
ret = readx_poll_timeout(anx7625_read_hpd_status_p0,
ctx, val,
((val & HPD_STATUS) || (val < 0)),
--
2.25.1
next reply other threads:[~2023-09-22 9:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 9:34 Xin Ji [this message]
2023-09-25 10:48 ` Robert Foss
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