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authorKrunoslav Kovac <Krunoslav.Kovac@amd.com>2020-08-06 17:54:47 -0400
committerAlex Deucher <alexander.deucher@amd.com>2020-08-18 18:01:21 -0400
commitd2e59d0ff4c44d1f6f8ed884a5bea7d1bb7fd98c (patch)
tree848e6e3b5e1c708c555ad9aca80db30034f760db
parentdb0473f62438e075b6832fd1490fd06d03c59372 (diff)
drm/amd/display: fix pow() crashing when given base 0
[Why&How] pow(a,x) is implemented as exp(x*log(a)). log(0) will crash. So return 0^x = 0, unless x=0, convention seems to be 0^0 = 1. Cc: stable@vger.kernel.org Signed-off-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com> Reviewed-by: Anthony Koo <Anthony.Koo@amd.com> Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
-rw-r--r--drivers/gpu/drm/amd/display/include/fixed31_32.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/include/fixed31_32.h b/drivers/gpu/drm/amd/display/include/fixed31_32.h
index 89ef9f6860e5..16df2a485dd0 100644
--- a/drivers/gpu/drm/amd/display/include/fixed31_32.h
+++ b/drivers/gpu/drm/amd/display/include/fixed31_32.h
@@ -431,6 +431,9 @@ struct fixed31_32 dc_fixpt_log(struct fixed31_32 arg);
*/
static inline struct fixed31_32 dc_fixpt_pow(struct fixed31_32 arg1, struct fixed31_32 arg2)
{
+ if (arg1.value == 0)
+ return arg2.value == 0 ? dc_fixpt_one : dc_fixpt_zero;
+
return dc_fixpt_exp(
dc_fixpt_mul(
dc_fixpt_log(arg1),