From: Andy Shevchenko Date: Fri, 20 Mar 2026 14:36:46 +0000 (+0100) Subject: fbdev: matroxfb: Mark variable with __maybe_unused to avoid W=1 build break X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=caf6144053b4e1c815aa56afb54745a176f999df;p=thirdparty%2Fkernel%2Flinux.git fbdev: matroxfb: Mark variable with __maybe_unused to avoid W=1 build break 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 --- diff --git a/drivers/video/fbdev/matrox/g450_pll.c b/drivers/video/fbdev/matrox/g450_pll.c index e2c1478aa47f..6a08f78cd1ac 100644 --- a/drivers/video/fbdev/matrox/g450_pll.c +++ b/drivers/video/fbdev/matrox/g450_pll.c @@ -409,7 +409,7 @@ 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);