On Wed, 25 Mar 2020 at 21:23, George Spelvin <lkml@xxxxxxx> wrote: > > igt_mm_config() calls ilog2() on the (pseudo)random 21-bit number > s>>12. Once in 2 million seeds, this is zero and ilog2 summons > the nasal demons. > > There was an attempt to handle this case with a max(), but that's > too late; ms could already be something bizarre. > > Given that the low 12 bits of s and ms are always zero, it's a lot > simpler just to divide them by 4096, then everything fits into 32 > bits, and we can easily generate a random number 1 <= s <= 0x1fffff. > > Signed-off-by: George Spelvin <lkml@xxxxxxx> > Fixes: 14d1b9a6247c > Cc: Matthew Auld <matthew.auld@xxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx> _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
