[PATCH 46/67] drm/amd/display: Disable DMCUB timeout for DCN35

[Zaeem Mohamed]

From: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>

[Why]
DMCUB can intermittently take longer than expected to process commands.

Old ASIC policy was to continue while logging a diagnostic error - which
works fine for ASIC without IPS, but with IPS this could lead to a race
condition where we attempt to access DCN state while it's inaccessible,
leading to a system hang when the NIU port is not disabled or register
accesses that timeout and the display configuration in an undefined
state.

[How]
We need to investigate why these accesses take longer than expected, but
for now we should disable the timeout on DCN35 to avoid this race
condition. Since the waits happen only at lower interrupt levels the
risk of taking too long at higher IRQ and causing a system watchdog
timeout are minimal.

Reviewed-by: Ovidiu Bunea <user did not set an email>
Acked-by: Zaeem Mohamed <zaeem.mohamed at amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
---
 drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c
index 391f9f69a923..5edccd565b05 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c
@@ -785,6 +785,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	.ips2_entry_delay_us = 800,
 	.disable_dmub_reallow_idle = false,
 	.static_screen_wait_frames = 2,
+	.disable_timeout = true,
 };
 
 static const struct dc_panel_config panel_config_defaults = {
-- 
2.34.1