[PATCH] drm/amdgpu: fix identifying prefix and postfix SET_Q_MODE packet

[ZhenGuo Yin]

[Why]
In legacy mode(no MCBP support) shadow_va of prefix SET_Q_MODE
packet is set to 0, matching the value used in the postfix
SET_Q_MODE packet. A prefix SET_Q_MODE packet will be skipped
unexpectedly when mixed running jobs with shadowing on and off.

[How]
Both shadow_va and vmid should be set to 0 in postfix SET_Q_MODE
packet. Combined these two conditions together to identify the
prefix and postfix SET_Q_MODE packet.

Fixes: 8bc75586ea01 ("drm/amdgpu: workaround to avoid SET_Q_MODE packets v2")
Signed-off-by: ZhenGuo Yin <zhenguo....@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c 
b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
index 5aff8f72de9c..01b9dfe5b307 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
@@ -5862,6 +5862,7 @@ static void gfx_v11_0_ring_emit_gfx_shadow(struct 
amdgpu_ring *ring,
 {
        struct amdgpu_device *adev = ring->adev;
        unsigned int offs, end;
+       bool is_postfix = !shadow_va && !vmid;
 
        if (!adev->gfx.cp_gfx_shadow || !ring->ring_obj)
                return;
@@ -5886,7 +5887,7 @@ static void gfx_v11_0_ring_emit_gfx_shadow(struct 
amdgpu_ring *ring,
         * the postfix SET_Q_MODE packet. This is changed below with a
         * WRITE_DATA command when the postfix executed.
         */
-       amdgpu_ring_write(ring, shadow_va ? 1 : 0);
+       amdgpu_ring_write(ring, is_postfix ? 0 : 1);
        amdgpu_ring_write(ring, 0);
 
        if (ring->set_q_mode_offs) {
@@ -5901,7 +5902,7 @@ static void gfx_v11_0_ring_emit_gfx_shadow(struct 
amdgpu_ring *ring,
         * When the postfix SET_Q_MODE packet executes we need to make sure 
that the
         * next prefix SET_Q_MODE packet executes as well.
         */
-       if (!shadow_va) {
+       if (is_postfix) {
                uint64_t addr;
 
                addr = amdgpu_bo_gpu_offset(ring->ring_obj);
@@ -5928,7 +5929,7 @@ static void gfx_v11_0_ring_emit_gfx_shadow(struct 
amdgpu_ring *ring,
        if (ring->set_q_mode_offs)
                amdgpu_ring_patch_cond_exec(ring, end);
 
-       if (shadow_va) {
+       if (!is_postfix) {
                uint64_t token = shadow_va ^ csa_va ^ gds_va ^ vmid;
 
                /*
-- 
2.35.1