[PATCH] drm/amd/powerplay: don't give up if DPM is already running

[Grazvydas Ignotas]

Currently the driver crashes if smu7_enable_dpm_tasks() returns early,
which it does if DPM is already active. It seems to be better just to
continue anyway, at least I haven't noticed any ill effects. It's also
unclear at what state the hardware was left by the previous driver, so
IMO it's better to always fully initialize.

Way to reproduce:
$ modprobe amdgpu
$ rmmod amdgpu
$ modprobe amdgpu
...
DPM is already running right now, no need to enable DPM!
...
failed to send message 18b ret is 0
BUG: unable to handle kernel paging request at ffffed01fc9ab21f
Call Trace:
 smu7_set_power_state_tasks+0x499/0x1940 [amdgpu]
 phm_set_power_state+0xcb/0x120 [amdgpu]
 psm_adjust_power_state_dynamic+0x11e/0x1b0 [amdgpu]
 pem_task_adjust_power_state+0xb9/0xd0 [amdgpu]
 pem_excute_event_chain+0x7d/0xe0 [amdgpu]
 pem_handle_event_unlocked+0x49/0x60 [amdgpu]
 pem_handle_event+0xe/0x10 [amdgpu]
 pp_dpm_dispatch_tasks+0xe0/0x190 [amdgpu]
 amdgpu_pm_compute_clocks+0x10c/0xc60 [amdgpu]
 dce_v11_0_crtc_dpms+0x7d/0x150 [amdgpu]
 dce_v11_0_crtc_disable+0x90/0x4a0 [amdgpu]
 drm_helper_disable_unused_functions+0x67/0x80 [drm_kms_helper]
 amdgpu_fbdev_init+0x13e/0x170 [amdgpu]
 amdgpu_device_init+0x1aeb/0x2490 [amdgpu]

Signed-off-by: Grazvydas Ignotas <notasas at gmail.com>
---
 drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
index f6afa6a..327030b 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c
@@ -1166,8 +1166,8 @@ static int smu7_enable_dpm_tasks(struct pp_hwmgr *hwmgr)
 
 	tmp_result = (!smum_is_dpm_running(hwmgr)) ? 0 : -1;
 	PP_ASSERT_WITH_CODE(tmp_result == 0,
-			"DPM is already running right now, no need to enable DPM!",
-			return 0);
+			"DPM is already running",
+			);
 
 	if (smu7_voltage_control(hwmgr)) {
 		tmp_result = smu7_enable_voltage_control(hwmgr);
-- 
2.7.4