Re: [PATCH] drm/amdgpu: use native mode for dp aux transfer

From: kernel test robot
Date: Fri Aug 12 2022 - 16:10:29 EST


Hi Zhenneng,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on linus/master v5.19 next-20220812]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Zhenneng-Li/drm-amdgpu-use-native-mode-for-dp-aux-transfer/20220811-193443
base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
config: s390-randconfig-r034-20220812 (https://download.01.org/0day-ci/archive/20220813/202208130320.NDvnbeVL-lkp@xxxxxxxxx/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 5f1c7e2cc5a3c07cbc2412e851a7283c1841f520)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install s390 cross compiling tool for clang build
# apt-get install binutils-s390x-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/1098c6fecb4292d634dbdccff9e720400dc7138d
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Zhenneng-Li/drm-amdgpu-use-native-mode-for-dp-aux-transfer/20220811-193443
git checkout 1098c6fecb4292d634dbdccff9e720400dc7138d
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/gpu/drm/amd/amdgpu/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

In file included from drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c:25:
In file included from drivers/gpu/drm/amd/amdgpu/../amdgpu/amdgpu.h:52:
In file included from include/linux/pci.h:39:
In file included from include/linux/io.h:13:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
#define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
^
include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
^
In file included from drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c:25:
In file included from drivers/gpu/drm/amd/amdgpu/../amdgpu/amdgpu.h:52:
In file included from include/linux/pci.h:39:
In file included from include/linux/io.h:13:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
^
include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
^
In file included from drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c:25:
In file included from drivers/gpu/drm/amd/amdgpu/../amdgpu/amdgpu.h:52:
In file included from include/linux/pci.h:39:
In file included from include/linux/io.h:13:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
>> drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c:73:10: warning: no previous prototype for function 'venus_mm_rreg_slow' [-Wmissing-prototypes]
uint32_t venus_mm_rreg_slow(struct amdgpu_device *adev, uint32_t reg)
^
drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c:73:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
uint32_t venus_mm_rreg_slow(struct amdgpu_device *adev, uint32_t reg)
^
static
>> drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c:84:6: warning: no previous prototype for function 'venus_mm_wreg_slow' [-Wmissing-prototypes]
void venus_mm_wreg_slow(struct amdgpu_device *adev, uint32_t reg, uint32_t v)
^
drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c:84:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void venus_mm_wreg_slow(struct amdgpu_device *adev, uint32_t reg, uint32_t v)
^
static
14 warnings generated.


vim +/venus_mm_rreg_slow +73 drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c

69
70 #define R100_MM_INDEX 0x0000
71 #define R100_MM_DATA 0x0004
72 #define AMDGPU_MIN_MMIO_SIZE 0x10000
> 73 uint32_t venus_mm_rreg_slow(struct amdgpu_device *adev, uint32_t reg)
74 {
75 unsigned long flags;
76 uint32_t ret;
77
78 spin_lock_irqsave(&adev->mmio_idx_lock, flags);
79 writel(reg, ((void __iomem *)adev->rmmio) + R100_MM_INDEX);
80 ret = readl(((void __iomem *)adev->rmmio) + R100_MM_DATA);
81 spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
82 return ret;
83 }
> 84 void venus_mm_wreg_slow(struct amdgpu_device *adev, uint32_t reg, uint32_t v)
85 {
86 unsigned long flags;
87
88 spin_lock_irqsave(&adev->mmio_idx_lock, flags);
89 writel(reg, ((void __iomem *)adev->rmmio) + R100_MM_INDEX);
90 writel(v, ((void __iomem *)adev->rmmio) + R100_MM_DATA);
91 spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
92 }
93 static inline uint32_t venus_mm_rreg(struct amdgpu_device *adev, uint32_t reg,
94 bool always_indirect)
95 {
96 /* The mmio size is 64kb at minimum. Allows the if to be optimized out. */
97 if ((reg < adev->rmmio_size || reg < AMDGPU_MIN_MMIO_SIZE) && !always_indirect)
98 return readl(((void __iomem *)adev->rmmio) + reg);
99 else
100 return venus_mm_rreg_slow(adev, reg);
101 }
102 static inline void venus_mm_wreg(struct amdgpu_device *adev, uint32_t reg, uint32_t v,
103 bool always_indirect)
104 {
105 if ((reg < adev->rmmio_size || reg < AMDGPU_MIN_MMIO_SIZE) && !always_indirect)
106 writel(v, ((void __iomem *)adev->rmmio) + reg);
107 else
108 venus_mm_wreg_slow(adev, reg, v);
109 }
110

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