[PATCH v2 1/2] drm/amdgpu: enhance amdgpu_vcn_suspend

[Zhu, James]

[AMD Official Use Only - Internal Distribution Only]

save_bo needn't ungate vcn,  it just keeps data in memory.


Thanks & Best Regards!


James Zhu

________________________________
From: Liu, Leo <Leo.Liu at amd.com>
Sent: Monday, May 17, 2021 2:07 PM
To: Zhu, James <James.Zhu at amd.com>; Zhu, James <James.Zhu at amd.com>; amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
Subject: Re: [PATCH v2 1/2] drm/amdgpu: enhance amdgpu_vcn_suspend


Definitely, we need to move cancel_delayed_work_sync moved to before power gate.

Should "save_bo" be step 4 before power gate ?

Regards,

Leo


On 2021-05-17 1:59 p.m., James Zhu wrote:

Then we forgot the proposal I provided before.

I think the below seq may fixed the race condition issue that we are facing.

1. stop scheduling new jobs

    for (i = 0; i < adev->vcn.num_vcn_inst; ++i) {
        if (adev->vcn.harvest_config & (1 << i))
            continue;

        ring = &adev->vcn.inst[i].ring_dec;
        ring->sched.ready = false;

        for (j = 0; j < adev->vcn.num_enc_rings; ++j) {
            ring = &adev->vcn.inst[i].ring_enc[j];
            ring->sched.ready = false;
        }
    }

2.    cancel_delayed_work_sync(&adev->vcn.idle_work);

3.    SOC15_WAIT_ON_RREG(VCN, inst_idx, mmUVD_POWER_STATUS, 1,
         UVD_POWER_STATUS__UVD_POWER_STATUS_MASK);

4.    amdgpu_device_ip_set_powergating_state(adev, AMD_IP_BLOCK_TYPE_VCN,   AMD_PG_STATE_GATE);

5.  saved_bo

Best Regards!

James

On 2021-05-17 1:43 p.m., Leo Liu wrote:

On 2021-05-17 12:54 p.m., James Zhu wrote:
I am wondering if there are still some jobs kept in the queue, it is lucky to check

Yes it's possible, in this case delayed handler is set, so cancelling once is enough.



UVD_POWER_STATUS done, but after, fw start a new job that list in the queue.

To handle this situation perfectly, we need add mechanism to suspend fw first.

I think that should be handled by the sequence from vcn_v3_0_stop_dpg_mode().



Another case, if it is unlucky, that  vcn fw hung at that time, UVD_POWER_STATUS

always keeps busy.   then it needs force powering gate the vcn hw after certain time waiting.

Yep, we still need to gate VCN power after certain timeout.


Regards,

Leo




Best Regards!

James

On 2021-05-17 12:34 p.m., Leo Liu wrote:

On 2021-05-17 11:52 a.m., James Zhu wrote:
During vcn suspends, stop ring continue to receive new requests,
and try to wait for all vcn jobs to finish gracefully.

v2: Forced powering gate vcn hardware after few wainting retry.

Signed-off-by: James Zhu <James.Zhu at amd.com><mailto:James.Zhu at amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c | 22 +++++++++++++++++++++-
  1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
index 2016459..9f3a6e7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
@@ -275,9 +275,29 @@ int amdgpu_vcn_suspend(struct amdgpu_device *adev)
  {
      unsigned size;
      void *ptr;
+    int retry_max = 6;
      int i;
  -    cancel_delayed_work_sync(&adev->vcn.idle_work);
+    for (i = 0; i < adev->vcn.num_vcn_inst; ++i) {
+        if (adev->vcn.harvest_config & (1 << i))
+            continue;
+        ring = &adev->vcn.inst[i].ring_dec;
+        ring->sched.ready = false;
+
+        for (j = 0; j < adev->vcn.num_enc_rings; ++j) {
+            ring = &adev->vcn.inst[i].ring_enc[j];
+            ring->sched.ready = false;
+        }
+    }
+
+    while (retry_max-- && cancel_delayed_work_sync(&adev->vcn.idle_work))
+        mdelay(5);

I think it's possible to have one pending job unprocessed with VCN when suspend sequence getting here, but it shouldn't be more than one, cancel_delayed_work_sync probably return false after the first time, so calling cancel_delayed_work_sync once should be enough here. we probably need to wait longer from:

SOC15_WAIT_ON_RREG(VCN, inst_idx, mmUVD_POWER_STATUS, 1,
        UVD_POWER_STATUS__UVD_POWER_STATUS_MASK);

to make sure the unprocessed job get done.


Regards,

Leo


+    if (!retry_max && !amdgpu_sriov_vf(adev)) {
+        if (RREG32_SOC15(VCN, i, mmUVD_STATUS)) {
+            dev_warn(adev->dev, "Forced powering gate vcn hardware!");
+            vcn_v3_0_set_powergating_state(adev, AMD_PG_STATE_GATE);
+        }
+    }
        for (i = 0; i < adev->vcn.num_vcn_inst; ++i) {
          if (adev->vcn.harvest_config & (1 << i))
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/amd-gfx/attachments/20210517/3bec7f25/attachment.htm>