linux-kernel - [PATCH v4 3/4] drm/msm/dp: check main link status before start aux read

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: <1619048258-8717-4-git-send-email-khsieh@codeaurora.org>
Date:   Wed, 21 Apr 2021 16:37:37 -0700
From:   Kuogee Hsieh <khsieh@...eaurora.org>
To:     robdclark@...il.com, sean@...rly.run, swboyd@...omium.org
Cc:     Kuogee Hsieh <khsieh@...eaurora.org>, abhinavk@...eaurora.org,
        aravindh@...eaurora.org, airlied@...ux.ie, daniel@...ll.ch,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH v4 3/4] drm/msm/dp: check main link status before start aux read

Maybe when the cable is disconnected the DP phy should be shutdown and
some bit in the phy could effectively "cut off" the aux channel and then
NAKs would start coming through here in the DP controller I/O register
space. This patch have DP aux channel read/write to return NAK immediately
if DP controller connection status is in unplugged state.

Changes in V4:
-- split this patch as stand alone patch

Signed-off-by: Kuogee Hsieh <khsieh@...eaurora.org>
---
 drivers/gpu/drm/msm/dp/dp_aux.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index 7c22bfe..fae3806 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -343,6 +343,11 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 
 	mutex_lock(&aux->mutex);
 
+	if (!dp_catalog_link_is_connected(aux->catalog)) {
+		ret = -ETIMEDOUT;
+		goto unlock_exit;
+	}
+
 	aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);
 
 	/* Ignore address only message */
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project