The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 96cb7cf13d8530099c256c053648ad576588c387 Mon Sep 17 00:00:00 2001

From: hersen wu hersenxs.wu@amd.com Date: Thu, 28 Feb 2019 16:35:24 -0500 Subject: [PATCH] drm/amd/display: disable dcn20 abm feature for bring up

[WHY] dcn20 enable usb-c dp ALT mode in dmcu. There is bug when enable abm feature which cause system crash. dal team will debug this bug later.

[HOW] disable dcn abm feature for dcn20.

Signed-off-by: hersen wu hersenxs.wu@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 5971aef4f033..72d14f680932 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -781,7 +781,7 @@ static int dm_late_init(void *handle) unsigned int linear_lut[16]; int i; struct dmcu *dmcu = adev->dm.dc->res_pool->dmcu; - bool ret; + bool ret = false;

for (i = 0; i < 16; i++) linear_lut[i] = 0xFFFF * i / 15; @@ -792,10 +792,13 @@ static int dm_late_init(void *handle) params.backlight_lut_array_size = 16; params.backlight_lut_array = linear_lut;

- ret = dmcu_load_iram(dmcu, params); + /* todo will enable for navi10 */ + if (adev->asic_type <= CHIP_RAVEN) { + ret = dmcu_load_iram(dmcu, params);

- if (!ret) - return -EINVAL; + if (!ret) + return -EINVAL; + }

return detect_mst_link_for_all_connectors(adev->ddev); }