This is a note to let you know that I've just added the patch titled
drm/amd/display: prevent potential division by zero errors
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-prevent-potential-division-by-zero-errors.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 07e388aab042774f284a2ad75a70a194517cdad4 Mon Sep 17 00:00:00 2001
From: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Date: Tue, 5 Sep 2023 13:27:22 -0400
Subject: drm/amd/display: prevent potential division by zero errors
From: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
commit 07e388aab042774f284a2ad75a70a194517cdad4 upstream.
There are two places in apply_below_the_range() where it's possible for
a divide by zero error to occur. So, to fix this make sure the divisor
is non-zero before attempting the computation in both cases.
Cc: stable@xxxxxxxxxxxxxxx
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2637
Fixes: a463b263032f ("drm/amd/display: Fix frames_to_insert math")
Fixes: ded6119e825a ("drm/amd/display: Reinstate LFC optimization")
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/display/modules/freesync/freesync.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
+++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
@@ -338,7 +338,9 @@ static void apply_below_the_range(struct
* - Delta for CEIL: delta_from_mid_point_in_us_1
* - Delta for FLOOR: delta_from_mid_point_in_us_2
*/
- if ((last_render_time_in_us / mid_point_frames_ceil) < in_out_vrr->min_duration_in_us) {
+ if (mid_point_frames_ceil &&
+ (last_render_time_in_us / mid_point_frames_ceil) <
+ in_out_vrr->min_duration_in_us) {
/* Check for out of range.
* If using CEIL produces a value that is out of range,
* then we are forced to use FLOOR.
@@ -385,8 +387,9 @@ static void apply_below_the_range(struct
/* Either we've calculated the number of frames to insert,
* or we need to insert min duration frames
*/
- if (last_render_time_in_us / frames_to_insert <
- in_out_vrr->min_duration_in_us){
+ if (frames_to_insert &&
+ (last_render_time_in_us / frames_to_insert) <
+ in_out_vrr->min_duration_in_us){
frames_to_insert -= (frames_to_insert > 1) ?
1 : 0;
}
Patches currently in stable-queue which might be from hamza.mahfooz@xxxxxxx are
queue-6.1/drm-amd-display-always-switch-off-odm-before-committing-more-streams.patch
queue-6.1/drm-amd-display-remove-wait-while-locked.patch
queue-6.1/drm-amd-display-prevent-potential-division-by-zero-errors.patch
queue-6.1/drm-amdgpu-register-a-dirty-framebuffer-callback-for-fbcon.patch
