[PATCH V2] drm/amd/pm: fix the deadlock issue observed on SI
Thorsten Leemhuis
regressions at leemhuis.info
Thu Apr 21 08:29:09 UTC 2022
On 11.04.22 10:54, Evan Quan wrote:
> The adev->pm.mutx is already held at the beginning of
> amdgpu_dpm_compute_clocks/amdgpu_dpm_enable_uvd/amdgpu_dpm_enable_vce.
> But on their calling path, amdgpu_display_bandwidth_update will be
> called and thus its sub functions amdgpu_dpm_get_sclk/mclk. They
> will then try to acquire the same adev->pm.mutex and deadlock will
> occur.
>
> By placing amdgpu_display_bandwidth_update outside of adev->pm.mutex
> protection(considering logically they do not need such protection) and
> restructuring the call flow accordingly, we can eliminate the deadlock
> issue. This comes with no real logics change.
>
> Fixes: 3712e7a49459 ("drm/amd/pm: unified lock protections in amdgpu_dpm.c")
> Reported-by: Paul Menzel <pmenzel at molgen.mpg.de>
> Reported-by: Arthur Marsh <arthur.marsh at internode.on.net>
> Link: https: //lore.kernel.org/all/9e689fea-6c69-f4b0-8dee-32c4cf7d8f9c at molgen.mpg.de/
> BugLink: https: //gitlab.freedesktop.org/drm/amd/-/issues/1957
Side note: two spaces sneaked in there. But that's not why I write this
mail.
This patch is fixing a regression in 5.18-rc, but it looks like things
are stuck for more than a week now. What's up there? Or was progress
made somewhere and I just couldn't find it? Was the review comment from
Lijo addressed?
Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
P.S.: As the Linux kernel's regression tracker I'm getting a lot of
reports on my table. I can only look briefly into most of them and lack
knowledge about most of the areas they concern. I thus unfortunately
will sometimes get things wrong or miss something important. I hope
that's not the case here; if you think it is, don't hesitate to tell me
in a public reply, it's in everyone's interest to set the public record
straight.
#regzbot ignore-activity
#regzbot ^backmonitor:
https://lore.kernel.org/all/9e689fea-6c69-f4b0-8dee-32c4cf7d8f9c@molgen.mpg.de/
> Signed-off-by: Evan Quan <evan.quan at amd.com>
> --
> v1->v2:
> - rich the commit messages(Paul)
> ---
> drivers/gpu/drm/amd/pm/amdgpu_dpm.c | 39 +++++++++++++++++++
> .../gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c | 10 -----
> drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c | 35 -----------------
> .../gpu/drm/amd/pm/powerplay/amd_powerplay.c | 10 -----
> 4 files changed, 39 insertions(+), 55 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> index 5504d81c77b7..72e7b5d40af6 100644
> --- a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> @@ -427,6 +427,7 @@ int amdgpu_dpm_read_sensor(struct amdgpu_device *adev, enum amd_pp_sensors senso
> void amdgpu_dpm_compute_clocks(struct amdgpu_device *adev)
> {
> const struct amd_pm_funcs *pp_funcs = adev->powerplay.pp_funcs;
> + int i;
>
> if (!adev->pm.dpm_enabled)
> return;
> @@ -434,6 +435,15 @@ void amdgpu_dpm_compute_clocks(struct amdgpu_device *adev)
> if (!pp_funcs->pm_compute_clocks)
> return;
>
> + if (adev->mode_info.num_crtc)
> + amdgpu_display_bandwidth_update(adev);
> +
> + for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
> + struct amdgpu_ring *ring = adev->rings[i];
> + if (ring && ring->sched.ready)
> + amdgpu_fence_wait_empty(ring);
> + }
> +
> mutex_lock(&adev->pm.mutex);
> pp_funcs->pm_compute_clocks(adev->powerplay.pp_handle);
> mutex_unlock(&adev->pm.mutex);
> @@ -443,6 +453,20 @@ void amdgpu_dpm_enable_uvd(struct amdgpu_device *adev, bool enable)
> {
> int ret = 0;
>
> + if (adev->family == AMDGPU_FAMILY_SI) {
> + mutex_lock(&adev->pm.mutex);
> + if (enable) {
> + adev->pm.dpm.uvd_active = true;
> + adev->pm.dpm.state = POWER_STATE_TYPE_INTERNAL_UVD;
> + } else {
> + adev->pm.dpm.uvd_active = false;
> + }
> + mutex_unlock(&adev->pm.mutex);
> +
> + amdgpu_dpm_compute_clocks(adev);
> + return;
> + }
> +
> ret = amdgpu_dpm_set_powergating_by_smu(adev, AMD_IP_BLOCK_TYPE_UVD, !enable);
> if (ret)
> DRM_ERROR("Dpm %s uvd failed, ret = %d. \n",
> @@ -453,6 +477,21 @@ void amdgpu_dpm_enable_vce(struct amdgpu_device *adev, bool enable)
> {
> int ret = 0;
>
> + if (adev->family == AMDGPU_FAMILY_SI) {
> + mutex_lock(&adev->pm.mutex);
> + if (enable) {
> + adev->pm.dpm.vce_active = true;
> + /* XXX select vce level based on ring/task */
> + adev->pm.dpm.vce_level = AMD_VCE_LEVEL_AC_ALL;
> + } else {
> + adev->pm.dpm.vce_active = false;
> + }
> + mutex_unlock(&adev->pm.mutex);
> +
> + amdgpu_dpm_compute_clocks(adev);
> + return;
> + }
> +
> ret = amdgpu_dpm_set_powergating_by_smu(adev, AMD_IP_BLOCK_TYPE_VCE, !enable);
> if (ret)
> DRM_ERROR("Dpm %s vce failed, ret = %d. \n",
> diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
> index 9613c6181c17..d3fe149d8476 100644
> --- a/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
> @@ -1028,16 +1028,6 @@ static int amdgpu_dpm_change_power_state_locked(struct amdgpu_device *adev)
> void amdgpu_legacy_dpm_compute_clocks(void *handle)
> {
> struct amdgpu_device *adev = (struct amdgpu_device *)handle;
> - int i = 0;
> -
> - if (adev->mode_info.num_crtc)
> - amdgpu_display_bandwidth_update(adev);
> -
> - for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
> - struct amdgpu_ring *ring = adev->rings[i];
> - if (ring && ring->sched.ready)
> - amdgpu_fence_wait_empty(ring);
> - }
>
> amdgpu_dpm_get_active_displays(adev);
>
> diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
> index caae54487f9c..633dab14f51c 100644
> --- a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
> @@ -3892,40 +3892,6 @@ static int si_set_boot_state(struct amdgpu_device *adev)
> }
> #endif
>
> -static int si_set_powergating_by_smu(void *handle,
> - uint32_t block_type,
> - bool gate)
> -{
> - struct amdgpu_device *adev = (struct amdgpu_device *)handle;
> -
> - switch (block_type) {
> - case AMD_IP_BLOCK_TYPE_UVD:
> - if (!gate) {
> - adev->pm.dpm.uvd_active = true;
> - adev->pm.dpm.state = POWER_STATE_TYPE_INTERNAL_UVD;
> - } else {
> - adev->pm.dpm.uvd_active = false;
> - }
> -
> - amdgpu_legacy_dpm_compute_clocks(handle);
> - break;
> - case AMD_IP_BLOCK_TYPE_VCE:
> - if (!gate) {
> - adev->pm.dpm.vce_active = true;
> - /* XXX select vce level based on ring/task */
> - adev->pm.dpm.vce_level = AMD_VCE_LEVEL_AC_ALL;
> - } else {
> - adev->pm.dpm.vce_active = false;
> - }
> -
> - amdgpu_legacy_dpm_compute_clocks(handle);
> - break;
> - default:
> - break;
> - }
> - return 0;
> -}
> -
> static int si_set_sw_state(struct amdgpu_device *adev)
> {
> return (amdgpu_si_send_msg_to_smc(adev, PPSMC_MSG_SwitchToSwState) == PPSMC_Result_OK) ?
> @@ -8125,7 +8091,6 @@ static const struct amd_pm_funcs si_dpm_funcs = {
> .print_power_state = &si_dpm_print_power_state,
> .debugfs_print_current_performance_level = &si_dpm_debugfs_print_current_performance_level,
> .force_performance_level = &si_dpm_force_performance_level,
> - .set_powergating_by_smu = &si_set_powergating_by_smu,
> .vblank_too_short = &si_dpm_vblank_too_short,
> .set_fan_control_mode = &si_dpm_set_fan_control_mode,
> .get_fan_control_mode = &si_dpm_get_fan_control_mode,
> diff --git a/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c b/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c
> index dbed72c1e0c6..1eb4e613b27a 100644
> --- a/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c
> +++ b/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c
> @@ -1503,16 +1503,6 @@ static void pp_pm_compute_clocks(void *handle)
> {
> struct pp_hwmgr *hwmgr = handle;
> struct amdgpu_device *adev = hwmgr->adev;
> - int i = 0;
> -
> - if (adev->mode_info.num_crtc)
> - amdgpu_display_bandwidth_update(adev);
> -
> - for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
> - struct amdgpu_ring *ring = adev->rings[i];
> - if (ring && ring->sched.ready)
> - amdgpu_fence_wait_empty(ring);
> - }
>
> if (!amdgpu_device_has_dc_support(adev)) {
> amdgpu_dpm_get_active_displays(adev);
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