Re: [PATCH v6 3/9] v4l: platform: Add Renesas CEU driver

kbuild test robot
2018-01-20T02:12:10Z

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Hi Jacopo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.15-rc8]
[cannot apply to linuxtv-media/master next-20180119]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Jacopo-Mondi/Renesas-Capture-Engine-Unit-CEU-V4L2-driver/20180120-053007
config: mn10300-allmodconfig (attached as .config)
compiler: am33_2.0-linux-gcc (GCC) 7.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=mn10300

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

In file included from include/linux/scatterlist.h:9:0,
from include/linux/dma-mapping.h:11,
from drivers/media/platform/renesas-ceu.c:16:
drivers/media/platform/renesas-ceu.c: In function 'ceu_start_streaming':
>> arch/mn10300/include/asm/io.h:63:25: warning: 'cdwdr' may be used uninitialized in this function [-Wmaybe-uninitialized]
*(volatile u32 *) addr = b;
~~~~~~~~~~~~~~~~~~~~~~~^~~
drivers/media/platform/renesas-ceu.c:335:27: note: 'cdwdr' was declared here
u32 camcr, cdocr, cfzsr, cdwdr, capwr;
^~~~~
In file included from include/linux/scatterlist.h:9:0,
from include/linux/dma-mapping.h:11,
from drivers/media/platform/renesas-ceu.c:16:
>> arch/mn10300/include/asm/io.h:63:25: warning: 'cfzsr' may be used uninitialized in this function [-Wmaybe-uninitialized]
*(volatile u32 *) addr = b;
~~~~~~~~~~~~~~~~~~~~~~~^~~
drivers/media/platform/renesas-ceu.c:335:20: note: 'cfzsr' was declared here
u32 camcr, cdocr, cfzsr, cdwdr, capwr;
^~~~~
drivers/media/platform/renesas-ceu.c:415:8: warning: 'camcr' may be used uninitialized in this function [-Wmaybe-uninitialized]
camcr |= mbus_flags & V4L2_MBUS_HSYNC_ACTIVE_LOW ? 1 << 0 : 0;
~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/platform/renesas-ceu.c:335:6: note: 'camcr' was declared here
u32 camcr, cdocr, cfzsr, cdwdr, capwr;
^~~~~
drivers/media/platform/renesas-ceu.c: In function 'ceu_probe':
drivers/media/platform/renesas-ceu.c:1621:9: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
return ret;
^~~
--
In file included from include/linux/scatterlist.h:9:0,
from include/linux/dma-mapping.h:11,
from drivers/media//platform/renesas-ceu.c:16:
drivers/media//platform/renesas-ceu.c: In function 'ceu_start_streaming':
>> arch/mn10300/include/asm/io.h:63:25: warning: 'cdwdr' may be used uninitialized in this function [-Wmaybe-uninitialized]
*(volatile u32 *) addr = b;
~~~~~~~~~~~~~~~~~~~~~~~^~~
drivers/media//platform/renesas-ceu.c:335:27: note: 'cdwdr' was declared here
u32 camcr, cdocr, cfzsr, cdwdr, capwr;
^~~~~
In file included from include/linux/scatterlist.h:9:0,
from include/linux/dma-mapping.h:11,
from drivers/media//platform/renesas-ceu.c:16:
>> arch/mn10300/include/asm/io.h:63:25: warning: 'cfzsr' may be used uninitialized in this function [-Wmaybe-uninitialized]
*(volatile u32 *) addr = b;
~~~~~~~~~~~~~~~~~~~~~~~^~~
drivers/media//platform/renesas-ceu.c:335:20: note: 'cfzsr' was declared here
u32 camcr, cdocr, cfzsr, cdwdr, capwr;
^~~~~
drivers/media//platform/renesas-ceu.c:415:8: warning: 'camcr' may be used uninitialized in this function [-Wmaybe-uninitialized]
camcr |= mbus_flags & V4L2_MBUS_HSYNC_ACTIVE_LOW ? 1 << 0 : 0;
~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media//platform/renesas-ceu.c:335:6: note: 'camcr' was declared here
u32 camcr, cdocr, cfzsr, cdwdr, capwr;
^~~~~
drivers/media//platform/renesas-ceu.c: In function 'ceu_probe':
drivers/media//platform/renesas-ceu.c:1621:9: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
return ret;
^~~

vim +/cdwdr +63 arch/mn10300/include/asm/io.h

b920de1b include/asm-mn10300/io.h David Howells 2008-02-08 60
b920de1b include/asm-mn10300/io.h David Howells 2008-02-08 61 static inline void writel(u32 b, volatile void __iomem *addr)
b920de1b include/asm-mn10300/io.h David Howells 2008-02-08 62 {
b920de1b include/asm-mn10300/io.h David Howells 2008-02-08 @63 *(volatile u32 *) addr = b;
b920de1b include/asm-mn10300/io.h David Howells 2008-02-08 64 }
b920de1b include/asm-mn10300/io.h David Howells 2008-02-08 65

:::::: The code at line 63 was first introduced by commit
:::::: b920de1b77b72ca9432ac3f97edb26541e65e5dd mn10300: add the MN10300/AM33 architecture to the kernel

:::::: TO: David Howells <dhowells@redhat.com>
:::::: CC: Linus Torvalds <torvalds@woody.linux-foundation.org>

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