linux-kernel - [PATCH v2 3/3] drm/bridge: parade-ps8640: Perform full poweroff if poweron fails

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211102093618.114928-3-angelogioacchino.delregno@collabora.com>
Date:   Tue,  2 Nov 2021 10:36:18 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     a.hajda@...sung.com
Cc:     narmstrong@...libre.com, robert.foss@...aro.org,
        Laurent.pinchart@...asonboard.com, jonas@...boo.se,
        jernej.skrabec@...il.com, airlied@...ux.ie, daniel@...ll.ch,
        dri-devel@...ts.freedesktop.org, kernel@...labora.com,
        linux-kernel@...r.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Subject: [PATCH v2 3/3] drm/bridge: parade-ps8640: Perform full poweroff if poweron fails

In function ps8640_bridge_poweron(), in case of a failure not relative
to the regulators enablement, the code was disabling the regulators but
the gpio changes that happened during the poweron sequence were not
being reverted back to a clean poweroff state.

Since it is expected that, when we enter ps8640_bridge_poweron(), the
powerdown and reset GPIOs are both in active state exactly as they were
left in the poweroff function before, we can simply call function
__ps8640_bridge_poweroff() in the failure case, reverting every change
that was done during the power on sequence.

Of course it was chosen to call the poweroff function instead of adding
code to revert the GPIO changes to the poweron one to avoid duplicating
code, as we would be doing exactly what the poweroff function does.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/gpu/drm/bridge/parade-ps8640.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
index 41f5d511d516..ef1b51d8b676 100644
--- a/drivers/gpu/drm/bridge/parade-ps8640.c
+++ b/drivers/gpu/drm/bridge/parade-ps8640.c
@@ -344,7 +344,7 @@ static int ps8640_bridge_poweron(struct ps8640 *ps_bridge)
 
 	if (ret < 0) {
 		DRM_ERROR("failed read PAGE2_GPIO_H: %d\n", ret);
-		goto err_regulators_disable;
+		goto err_poweroff;
 	}
 
 	msleep(50);
@@ -360,23 +360,22 @@ static int ps8640_bridge_poweron(struct ps8640 *ps_bridge)
 	ret = regmap_update_bits(map, PAGE2_MCS_EN, MCS_EN, 0);
 	if (ret < 0) {
 		DRM_ERROR("failed write PAGE2_MCS_EN: %d\n", ret);
-		goto err_regulators_disable;
+		goto err_poweroff;
 	}
 
 	/* Switch access edp panel's edid through i2c */
 	ret = regmap_write(map, PAGE2_I2C_BYPASS, I2C_BYPASS_EN);
 	if (ret < 0) {
 		DRM_ERROR("failed write PAGE2_I2C_BYPASS: %d\n", ret);
-		goto err_regulators_disable;
+		goto err_poweroff;
 	}
 
 	ps_bridge->powered = true;
 
 	return 0;
 
-err_regulators_disable:
-	regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
-			       ps_bridge->supplies);
+err_poweroff:
+	__ps8640_bridge_poweroff(ps_bridge);
 
 	return ret;
 }
-- 
2.33.1