Hello Ramalingam C,
The patch 6498bf5800a3: "drm: revocation check at drm subsystem" from May 7, 2019, leads to the following static checker warning:
drivers/gpu/drm/drm_hdcp.c:195 drm_hdcp_parse_hdcp2_srm() warn: mask and shift to zero
drivers/gpu/drm/drm_hdcp.c 190 DRM_ERROR("No vrl found\n"); 191 return -EINVAL; 192 } 193 194 buf += DRM_HDCP_2_VRL_LENGTH_SIZE; 195 ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1)); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This macro is always zero.
196 if (!ksv_count) { 197 DRM_DEBUG("Revoked KSV count is 0\n"); 198 return count; 199 } 200
The define is:
#define DRM_HDCP_2_KSV_COUNT_2_LSBITS(byte) (((byte) & 0xC) >> 6)
0xC >> 6 is always zero.
regards, dan carpenter