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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Tom Rix <trix@redhat.com>,
        Robert Foss <robert.foss@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 258/879] drm/bridge: anx7625: check the return on anx7625_aux_trans
Date:   Tue,  7 Jun 2022 18:56:16 +0200
Message-Id: <20220607165010.338124319@linuxfoundation.org>
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From: Tom Rix <trix@redhat.com>

[ Upstream commit d583e752732421b26fef0d65020565f3bef12248 ]

Clang static analysis reports this issue
anx7625.c:876:13: warning: The left operand of '&' is
  a garbage value
  if (!(bcap & 0xOA01)) {
        ~~~~ ^

bcap is only set by a successful call to
anx7625_aux_trans().  So check.

Fixes: cd1637c7e480 ("drm/bridge: anx7625: add HDCP support")
Signed-off-by: Tom Rix <trix@redhat.com>
Fixes: adca62ec370c ("drm/bridge: anx7625: Support reading edid through aux channel")
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220303201943.501746-1-trix@redhat.com
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 31ecf5626f1d..8e1851a57638 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -874,7 +874,10 @@ static int anx7625_hdcp_enable(struct anx7625_data *ctx)
 	}
 
 	/* Read downstream capability */
-	anx7625_aux_trans(ctx, DP_AUX_NATIVE_READ, 0x68028, 1, &bcap);
+	ret = anx7625_aux_trans(ctx, DP_AUX_NATIVE_READ, 0x68028, 1, &bcap);
+	if (ret < 0)
+		return ret;
+
 	if (!(bcap & 0x01)) {
 		pr_warn("downstream not support HDCP 1.4, cap(%x).\n", bcap);
 		return 0;
-- 
2.35.1