Andy ShevchenkoandGreg Kroah-Hartman 6005b00f47 fbdev: matroxfb: Mark variable with __maybe_unused to avoid W=1 build break ...

[ Upstream commit caf6144053 ]

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 7b987887f9 ("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: 7b987887f9 ("video: fbdev: matroxfb: remove dead code and set but not used variable")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2026-06-01 17:39:10 +02:00

..

g450_pll.c

…

g450_pll.h

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i2c-matroxfb.c

…

Makefile

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matroxfb_accel.c

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matroxfb_accel.h

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matroxfb_base.c

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matroxfb_base.h

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matroxfb_crtc2.c

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matroxfb_crtc2.h

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matroxfb_DAC1064.c

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matroxfb_DAC1064.h

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matroxfb_g450.c

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matroxfb_g450.h

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matroxfb_maven.c

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matroxfb_maven.h

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matroxfb_misc.c

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matroxfb_misc.h

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matroxfb_Ti3026.c

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matroxfb_Ti3026.h

…