Re: [PATCH v7 drm-dp 1/4] drm/hisilicon/hibmc: fix dp probabilistical detect errors after HPD irq

[kernel test robot <lkp@intel.com>]

Hi Yongbang,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on linus/master v6.17-rc7 next-20250923]
[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/Yongbang-Shi/drm-hisilicon-hibmc-fix-dp-probabilistical-detect-errors-after-HPD-irq/20250923-211652
base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link:    https://lore.kernel.org/r/20250923130411.2522339-2-shiyongbang%40huawei.com
patch subject: [PATCH v7 drm-dp 1/4] drm/hisilicon/hibmc: fix dp probabilistical detect errors after HPD irq
config: s390-randconfig-001-20250924 (https://download.01.org/0day-ci/archive/20250924/202509241625.o4mNleVb-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250924/202509241625.o4mNleVb-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509241625.o4mNleVb-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c: In function 'hibmc_dp_detect':
>> drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c:61:18: warning: array subscript 128 is above array bounds of 'u8[15]' {aka 'unsigned char[15]'} [-Warray-bounds]
         dp_dev->dpcd[DP_DOWNSTREAM_PORT_0] & DP_DS_PORT_HPD) {
         ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~


vim +61 drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c

    34	
    35	static int hibmc_dp_detect(struct drm_connector *connector,
    36				   struct drm_modeset_acquire_ctx *ctx, bool force)
    37	{
    38		struct hibmc_dp *dp = to_hibmc_dp(connector);
    39		struct hibmc_dp_dev *dp_dev = dp->dp_dev;
    40		int ret;
    41	
    42		if (dp->irq_status) {
    43			if (dp_dev->hpd_status != HIBMC_HPD_IN)
    44				return connector_status_disconnected;
    45		}
    46	
    47		ret = drm_dp_read_dpcd_caps(dp_dev->aux, dp_dev->dpcd);
    48		if (ret)
    49			return connector_status_disconnected;
    50	
    51		dp_dev->is_branch = drm_dp_is_branch(dp_dev->dpcd);
    52	
    53		ret = drm_dp_read_desc(dp_dev->aux, &dp_dev->desc, dp_dev->is_branch);
    54		if (ret)
    55			return connector_status_disconnected;
    56	
    57		if (!dp_dev->is_branch)
    58			return connector_status_connected;
    59	
    60		if (drm_dp_read_sink_count_cap(connector, dp_dev->dpcd, &dp_dev->desc) &&
  > 61		    dp_dev->dpcd[DP_DOWNSTREAM_PORT_0] & DP_DS_PORT_HPD) {
    62			ret = drm_dp_read_sink_count(dp_dev->aux);
    63			if (ret > 0)
    64				return connector_status_connected;
    65		}
    66	
    67		return connector_status_disconnected;
    68	}
    69	

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