according to BUG:7120987 - base.BUG:6454631 from Version 10.2.0.4 onwards ASM does no longer see any block devices. I also tested and reproduced this in 126.96.36.199. Use character devices instead.
Only on Linux, you can still use block devices.
this doesn't seem to be rated as bug, more a kind of feature. so don't expect this to change back again.
This is also described in Note:601591.1 - After Upgrading to 10.2.0.4 or 188.8.131.52 Unable to discover disks using block devices and marked as expected behavior.