This is a note to let you know that I've just added the patch titled drm/amd/display: Use the correct max downscaling value for DCN3.x family to the 5.12-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-use-the-correct-max-downscaling-value-for-dcn3.x-family.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 84c63d040938f64a7dc195696301166e75231bf5 Mon Sep 17 00:00:00 2001 From: Nikola Cornij <nikola.cornij@xxxxxxx> Date: Thu, 6 May 2021 22:46:52 -0400 Subject: drm/amd/display: Use the correct max downscaling value for DCN3.x family From: Nikola Cornij <nikola.cornij@xxxxxxx> commit 84c63d040938f64a7dc195696301166e75231bf5 upstream. [why] As per spec, DCN3.x can do 6:1 downscaling and DCN2.x can do 4:1. The max downscaling limit value for DCN2.x is 250, which means it's calculated as 1000 / 4 = 250. For DCN3.x this then gives 1000 / 6 = 167. [how] Set maximum downscaling limit to 167 for DCN3.x Signed-off-by: Nikola Cornij <nikola.cornij@xxxxxxx> Reviewed-by: Charlene Liu <Charlene.Liu@xxxxxxx> Reviewed-by: Harry Wentland <Harry.Wentland@xxxxxxx> Acked-by: Stylon Wang <stylon.wang@xxxxxxx> Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c | 7 ++++--- drivers/gpu/drm/amd/display/dc/dcn301/dcn301_resource.c | 7 ++++--- drivers/gpu/drm/amd/display/dc/dcn302/dcn302_resource.c | 7 ++++--- 3 files changed, 12 insertions(+), 9 deletions(-) --- a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c +++ b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_resource.c @@ -826,10 +826,11 @@ static const struct dc_plane_cap plane_c .fp16 = 16000 }, + /* 6:1 downscaling ratio: 1000/6 = 166.666 */ .max_downscale_factor = { - .argb8888 = 600, - .nv12 = 600, - .fp16 = 600 + .argb8888 = 167, + .nv12 = 167, + .fp16 = 167 } }; --- a/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_resource.c +++ b/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_resource.c @@ -843,10 +843,11 @@ static const struct dc_plane_cap plane_c .fp16 = 16000 }, + /* 6:1 downscaling ratio: 1000/6 = 166.666 */ .max_downscale_factor = { - .argb8888 = 600, - .nv12 = 600, - .fp16 = 600 + .argb8888 = 167, + .nv12 = 167, + .fp16 = 167 }, 64, 64 --- a/drivers/gpu/drm/amd/display/dc/dcn302/dcn302_resource.c +++ b/drivers/gpu/drm/amd/display/dc/dcn302/dcn302_resource.c @@ -282,10 +282,11 @@ static const struct dc_plane_cap plane_c .nv12 = 16000, .fp16 = 16000 }, + /* 6:1 downscaling ratio: 1000/6 = 166.666 */ .max_downscale_factor = { - .argb8888 = 600, - .nv12 = 600, - .fp16 = 600 + .argb8888 = 167, + .nv12 = 167, + .fp16 = 167 }, 16, 16 Patches currently in stable-queue which might be from nikola.cornij@xxxxxxx are queue-5.12/drm-amd-display-use-the-correct-max-downscaling-value-for-dcn3.x-family.patch