From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CE61623392B; Sat, 30 May 2026 18:01:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780164063; cv=none; b=bu5LgXOAMbH5FpolFHwh1uVSy8+Ce078cnd4WA7dduCnpa65SAttPM+jSRGVRfk1EHKY2dfA8CCw1TWw22SnbmDOuC30BAQpqVARhlpVKm7ji9Xxz6YTDJW3DNjCxLLTiD58EJhxHGmF4w9SDeFmsp8tY9hxGN81OrHusggKp30= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780164063; c=relaxed/simple; bh=9BrOShu2XlnB3L2gK9PFuJcZc3zNCIR455wH9nb9lPw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E4iRxNNt483BHyLOpzTS7hSRzOGwHhpqMb2cKWY5esFBZsrAtLjBhX5oHfwXmgwfnl88bNwMUv6a1P/j9HlNVfkfTxWirEEag5866CAsKvPBPTp9DJQSxdEiWNoTxiLQhHp/7mzlL2F4twRZXoCEXMB3+JVSdR64Zp5xh8m8e7A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uiqZWBTp; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uiqZWBTp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 318021F00893; Sat, 30 May 2026 18:01:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780164062; bh=7oC0LpH7jbBTDQLzRPv9oogjbhvA31u2+L45852w1tI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=uiqZWBTpQ6qMnmo/XwprmlbLIEXssZM1pX7DDbxthKZFZzA72g2A8BstToi6ce1u8 yU4lTxRLtbJBf7uF+4oqF5HFdm3ohf3uUW6+C/8umSmjWJwrYOg944Hl+6C0HQxthD KaboxKuCo9Z+NBg6ZtehMLkj1z+2Xotcx5J1aU4o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andy Shevchenko , Jason Yan , Helge Deller , Sasha Levin Subject: [PATCH 5.15 444/776] fbdev: matroxfb: Mark variable with __maybe_unused to avoid W=1 build break Date: Sat, 30 May 2026 18:02:38 +0200 Message-ID: <20260530160251.883369274@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Shevchenko [ Upstream commit caf6144053b4e1c815aa56afb54745a176f999df ] Clang is not happy about set but unused variable: drivers/video/fbdev/matrox/g450_pll.c:412:18: error: variable 'mnp' set but not used 412 | unsigned int mnp; | ^ 1 error generated. Since the commit 7b987887f97b ("video: fbdev: matroxfb: remove dead code and set but not used variable") the 'mnp' became unused, but eliminating that code might have side-effects. The question here is what should we do with 'mnp'? The easiest way out is just mark it with __maybe_unused which will shut the compiler up and won't change any possible IO flow. So does this change. A dive into the history of the driver: The problem was revealed when the #if 0 guarded code along with unused pixel_vco variable was removed. That code was introduced in the original commit 213d22146d1f ("[PATCH] (1/3) matroxfb for 2.5.3"). And then guarded in the commit 705e41f82988 ("matroxfb DVI updates: Handle DVI output on G450/G550. Powerdown unused portions of G450/G550 DAC. Split G450/G550 DAC from older DAC1064 handling. Modify PLL setting when both CRTCs use same pixel clocks."). NOTE: The two commits mentioned above pre-date Git era and available in history.git repository for archaeological purposes. Even without that guard the modern compilers may see that the pixel_vco wasn't ever used and seems a leftover after some debug or review made 25 years ago. The g450_mnp2vco() doesn't have any IO and as Jason said doesn't seem to have any side effects either than some unneeded CPU processing during runtime. I agree that's unlikely that timeout (or heating up the CPU) has any effect on the HW (GPU/display) functionality. Fixes: 7b987887f97b ("video: fbdev: matroxfb: remove dead code and set but not used variable") Signed-off-by: Andy Shevchenko Reviewed-by: Jason Yan Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/matrox/g450_pll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/fbdev/matrox/g450_pll.c b/drivers/video/fbdev/matrox/g450_pll.c index ff8e321a22cef..b2d3f7328ea83 100644 --- a/drivers/video/fbdev/matrox/g450_pll.c +++ b/drivers/video/fbdev/matrox/g450_pll.c @@ -407,7 +407,7 @@ static int __g450_setclk(struct matrox_fb_info *minfo, unsigned int fout, case M_VIDEO_PLL: { u_int8_t tmp; - unsigned int mnp; + unsigned int mnp __maybe_unused; unsigned long flags; matroxfb_DAC_lock_irqsave(flags); -- 2.53.0