From f689e3acbd2e48cc4101e0af454193f81af4baaf Mon Sep 17 00:00:00 2001 From: Mikko Tiihonen Date: Wed, 30 Jan 2013 14:10:04 -0500 Subject: [PATCH] drm/radeon: protect against div by 0 in backend setup Make sure at least one RB is enabled in r6xx_remap_render_backend() to avoid an division by zero in some corner cases. See: https://bugzilla.redhat.com/show_bug.cgi?id=892233 Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org --- drivers/gpu/drm/radeon/r600.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c index bc2540b17c5e..becb03e8b32f 100644 --- a/drivers/gpu/drm/radeon/r600.c +++ b/drivers/gpu/drm/radeon/r600.c @@ -1462,12 +1462,15 @@ u32 r6xx_remap_render_backend(struct radeon_device *rdev, u32 disabled_rb_mask) { u32 rendering_pipe_num, rb_num_width, req_rb_num; - u32 pipe_rb_ratio, pipe_rb_remain; + u32 pipe_rb_ratio, pipe_rb_remain, tmp; u32 data = 0, mask = 1 << (max_rb_num - 1); unsigned i, j; /* mask out the RBs that don't exist on that asic */ - disabled_rb_mask |= (0xff << max_rb_num) & 0xff; + tmp = disabled_rb_mask | ((0xff << max_rb_num) & 0xff); + /* make sure at least one RB is available */ + if ((tmp & 0xff) != 0xff) + disabled_rb_mask = tmp; rendering_pipe_num = 1 << tiling_pipe_num; req_rb_num = total_max_rb_num - r600_count_pipe_bits(disabled_rb_mask); -- 2.39.5