[PATCH] drm/amdgpu/gfx10: re-init clear state buffer after gpu reset

[Yuan, Xiaojie]

Hi Hawking,

This is a formal fix I think.
As you suggested, I tried to dump csb in various locations in gpu reset sequence:
1. after gfx_v10_0_hw_fini() completes - csb still contains correct data
    |
    v
   baco reset
    |
    v
2. right after gmc resume - csb contains corrupted data

In this small time window, no firmware touches csb and it should prove that vram lost causes csb corrupt.

BR,
Xiaojie

________________________________________
From: Zhang, Hawking <Hawking.Zhang at amd.com>
Sent: Wednesday, November 20, 2019 4:43 PM
To: Yuan, Xiaojie; amd-gfx at lists.freedesktop.org
Cc: Xiao, Jack; Long, Gang
Subject: RE: [PATCH] drm/amdgpu/gfx10: re-init clear state buffer after gpu reset

Just make sure I understand you correctly. So until fw team root cause the reason of csb corruption, we keep the workaround in driver, correct?

Regards,
Hawking
-----Original Message-----
From: Yuan, Xiaojie <Xiaojie.Yuan at amd.com>
Sent: 2019年11月20日 14:47
To: amd-gfx at lists.freedesktop.org
Cc: Zhang, Hawking <Hawking.Zhang at amd.com>; Xiao, Jack <Jack.Xiao at amd.com>; Long, Gang <Gang.Long at amd.com>; Yuan, Xiaojie <Xiaojie.Yuan at amd.com>
Subject: [PATCH] drm/amdgpu/gfx10: re-init clear state buffer after gpu reset

This patch fixes 2nd baco reset failure with gfxoff enabled on navi1x.

clear state buffer (resides in vram) is corrupted after 1st baco reset, upon gfxoff exit, CPF gets garbage header in CSIB and hangs.

Signed-off-by: Xiaojie Yuan <xiaojie.yuan at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c | 43 ++++++++++++++++++++++----
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
index 9274bd4b6c68..8e24ea08ca39 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
@@ -1789,27 +1789,52 @@ static void gfx_v10_0_enable_gui_idle_interrupt(struct amdgpu_device *adev,
        WREG32_SOC15(GC, 0, mmCP_INT_CNTL_RING0, tmp);  }

-static void gfx_v10_0_init_csb(struct amdgpu_device *adev)
+static int gfx_v10_0_init_csb(struct amdgpu_device *adev)
 {
+       int r;
+
+       if (adev->in_gpu_reset) {
+               r = amdgpu_bo_reserve(adev->gfx.rlc.clear_state_obj, false);
+               if (r)
+                       return r;
+
+               r = amdgpu_bo_kmap(adev->gfx.rlc.clear_state_obj,
+                                  (void **)&adev->gfx.rlc.cs_ptr);
+               if (!r) {
+                       adev->gfx.rlc.funcs->get_csb_buffer(adev,
+                                       adev->gfx.rlc.cs_ptr);
+                       amdgpu_bo_kunmap(adev->gfx.rlc.clear_state_obj);
+               }
+
+               amdgpu_bo_unreserve(adev->gfx.rlc.clear_state_obj);
+               if (r)
+                       return r;
+       }
+
        /* csib */
        WREG32_SOC15(GC, 0, mmRLC_CSIB_ADDR_HI,
                     adev->gfx.rlc.clear_state_gpu_addr >> 32);
        WREG32_SOC15(GC, 0, mmRLC_CSIB_ADDR_LO,
                     adev->gfx.rlc.clear_state_gpu_addr & 0xfffffffc);
        WREG32_SOC15(GC, 0, mmRLC_CSIB_LENGTH, adev->gfx.rlc.clear_state_size);
+
+       return 0;
 }

-static void gfx_v10_0_init_pg(struct amdgpu_device *adev)
+static int gfx_v10_0_init_pg(struct amdgpu_device *adev)
 {
        int i;
+       int r;

-       gfx_v10_0_init_csb(adev);
+       r = gfx_v10_0_init_csb(adev);
+       if (r)
+               return r;

        for (i = 0; i < adev->num_vmhubs; i++)
                amdgpu_gmc_flush_gpu_tlb(adev, 0, i, 0);

        /* TODO: init power gating */
-       return;
+       return 0;
 }

 void gfx_v10_0_rlc_stop(struct amdgpu_device *adev) @@ -1911,7 +1936,10 @@ static int gfx_v10_0_rlc_resume(struct amdgpu_device *adev)
                r = gfx_v10_0_wait_for_rlc_autoload_complete(adev);
                if (r)
                        return r;
-               gfx_v10_0_init_pg(adev);
+
+               r = gfx_v10_0_init_pg(adev);
+               if (r)
+                       return r;

                /* enable RLC SRM */
                gfx_v10_0_rlc_enable_srm(adev);
@@ -1937,7 +1965,10 @@ static int gfx_v10_0_rlc_resume(struct amdgpu_device *adev)
                                return r;
                }

-               gfx_v10_0_init_pg(adev);
+               r = gfx_v10_0_init_pg(adev);
+               if (r)
+                       return r;
+
                adev->gfx.rlc.funcs->start(adev);

                if (adev->firmware.load_type == AMDGPU_FW_LOAD_RLC_BACKDOOR_AUTO) {
--
2.20.1