From: Douglas Anderson <dianders@chromium.org>
To: Thierry Reding <thierry.reding@gmail.com>,
Sam Ravnborg <sam@ravnborg.org>
Cc: Rob Clark <robdclark@chromium.org>,
Stephen Boyd <swboyd@chromium.org>,
Douglas Anderson <dianders@chromium.org>,
Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/5] drm/panel-simple: Don't wait longer for HPD than hpd_absent_delay
Date: Fri, 15 Jan 2021 14:44:17 -0800 [thread overview]
Message-ID: <20210115144345.v2.2.I183b1817610d7a82fdd3bc852e96d2985df9623f@changeid> (raw)
In-Reply-To: <20210115224420.1635017-1-dianders@chromium.org>
If a panel has an hpd_absent_delay specified then we know exactly how
long the maximum time is before HPD must be asserted. That means we
can use it as a timeout for polling the HPD pin instead of using an
arbitrary timeout. This is especially useful for dealing with panels
that periodically fail to power on and need to be retried. We can
detect the problem sooner.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Changes in v2:
- ("drm/panel-simple: Don't wait longer for HPD...") new for v2.
drivers/gpu/drm/panel/panel-simple.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 581ab6810b70..30842cf6d414 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -382,6 +382,7 @@ static int panel_simple_prepare(struct drm_panel *panel)
unsigned int delay;
int err;
int hpd_asserted;
+ unsigned long hpd_wait_us;
if (p->prepared_time != 0)
return 0;
@@ -409,9 +410,14 @@ static int panel_simple_prepare(struct drm_panel *panel)
goto error;
}
+ if (p->desc->delay.hpd_absent_delay)
+ hpd_wait_us = p->desc->delay.hpd_absent_delay * 1000UL;
+ else
+ hpd_wait_us = 2000000;
+
err = readx_poll_timeout(gpiod_get_value_cansleep, p->hpd_gpio,
hpd_asserted, hpd_asserted,
- 1000, 2000000);
+ 1000, hpd_wait_us);
if (hpd_asserted < 0)
err = hpd_asserted;
--
2.30.0.284.gd98b1dd5eaa7-goog
next prev parent reply other threads:[~2021-01-15 22:45 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-15 22:44 [PATCH v2 0/5] drm/panel-simple: Patches for N116BCA-EA1 Douglas Anderson
2021-01-15 22:44 ` [PATCH v2 1/5] drm/panel-simple: Undo enable if HPD never asserts Douglas Anderson
2021-01-15 22:49 ` Stephen Boyd
2021-01-15 22:44 ` Douglas Anderson [this message]
2021-01-25 20:26 ` [PATCH v2 2/5] drm/panel-simple: Don't wait longer for HPD than hpd_absent_delay Stephen Boyd
2021-01-15 22:44 ` [PATCH v2 3/5] drm/panel-simple: Retry if we timeout waiting for HPD Douglas Anderson
2021-01-25 20:28 ` Stephen Boyd
2021-01-27 21:11 ` Doug Anderson
2021-01-15 22:44 ` [PATCH v2 4/5] dt-bindings: dt-bindings: display: simple: Add N116BCA-EA1 Douglas Anderson
2021-01-15 22:59 ` Doug Anderson
2021-01-25 20:29 ` Stephen Boyd
2021-02-08 21:50 ` Rob Herring
2021-01-15 22:44 ` [PATCH v2 5/5] drm/panel-simple: " Douglas Anderson
2021-01-25 20:29 ` Stephen Boyd
2021-03-05 15:42 ` [PATCH v2 0/5] drm/panel-simple: Patches for N116BCA-EA1 Doug Anderson
2021-03-10 23:25 ` Linus Walleij
2021-03-10 23:47 ` Doug Anderson
2021-03-11 0:57 ` Linus Walleij
2021-03-11 1:01 ` Doug Anderson
2021-03-11 16:20 ` Linus Walleij
2021-03-11 16:15 ` Linus Walleij
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