From: Nicholas Kazlauskas nicholas.kazlauskas@amd.com
[ Upstream commit 7c70e60fbf4bff1123f0e8d5cb1ae71df6164d7f ]
[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 ovidiu.bunea@amd.com Acked-by: Zaeem Mohamed zaeem.mohamed@amd.com Signed-off-by: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 28c4599076989..915d68cc04e9c 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 = {