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drm/amd/display: fix potential integer overflow when shifting 32 bit variable bl_pwm

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The 32 bit unsigned integer bl_pwm is being shifted using 32 bit arithmetic
and then being assigned to a 64 bit unsigned integer.  There is a potential
for a 32 bit overflow so cast bl_pwm to enforce a 64 bit shift operation
to avoid this.

Addresses-Coverity: ("unintentional integer overflow")
Fixes: 3ba01817365c ("drm/amd/display: Move panel_cntl specific register from abm to panel_cntl.")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Colin Ian King 2020-08-18 13:09:14 +01:00 committed by Alex Deucher
parent 367deb673c
commit 1d5503331b
1 changed files with 1 additions and 1 deletions
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2
drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c
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@ -76,7 +76,7 @@ static unsigned int dce_get_16_bit_backlight_from_pwm(struct panel_cntl *panel_c
else
bl_pwm &= 0xFFFF;
current_backlight = bl_pwm << (1 + bl_int_count);
current_backlight = (uint64_t)bl_pwm << (1 + bl_int_count);
if (bl_period == 0)
bl_period = 0xFFFF;