4.18-stable review patch. If anyone has any objections, please let me know.
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From: Su Sung Chung Su.Chung@amd.com
[ Upstream commit 43c3ff27a47d83d153c4adc088243ba594582bf5 ]
[Why] A loop inside of build_evenly_distributed_points function that traverse through the array of points become an infinite loop when m_GammaUpdates does not get assigned to any value.
[How] In DMColor, clear m_gammaIsValid bit just before writting all Zeromem for m_GammaUpdates, to prevent calling build_evenly_distributed_points before m_GammaUpdates gets assigned to some value.
Signed-off-by: Su Sung Chung Su.Chung@amd.com Reviewed-by: Aric Cyr Aric.Cyr@amd.com Acked-by: Bhawanpreet Lakha Bhawanpreet.Lakha@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/modules/color/color_gamma.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/amd/display/modules/color/color_gamma.c +++ b/drivers/gpu/drm/amd/display/modules/color/color_gamma.c @@ -968,10 +968,14 @@ static void build_evenly_distributed_poi struct dividers dividers) { struct gamma_pixel *p = points; - struct gamma_pixel *p_last = p + numberof_points - 1; + struct gamma_pixel *p_last;
uint32_t i = 0;
+ // This function should not gets called with 0 as a parameter + ASSERT(numberof_points > 0); + p_last = p + numberof_points - 1; + do { struct fixed31_32 value = dc_fixpt_from_fraction(i, numberof_points - 1); @@ -982,7 +986,7 @@ static void build_evenly_distributed_poi
++p; ++i; - } while (i != numberof_points); + } while (i < numberof_points);
p->r = dc_fixpt_div(p_last->r, dividers.divider1); p->g = dc_fixpt_div(p_last->g, dividers.divider1);