Am 21.04.22 um 23:13 schrieb Zack Rusin:
On Thu, 2022-04-21 at 12:17 +0200, Christian König wrote:
⚠ External Email
Am 20.04.22 um 21:28 schrieb Zack Rusin:
[SNIP]
To figure out what it is could you try the following code
fragment:
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
index f46891012be3..a36f89d3f36d 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_validation.c
@@ -288,7 +288,7 @@ int vmw_validation_add_bo(struct
vmw_validation_context *ctx,
val_buf->bo = ttm_bo_get_unless_zero(&vbo-
base);
if (!val_buf->bo)
return -ESRCH;
- val_buf->num_shared = 0;
+ val_buf->num_shared = 16;
list_add_tail(&val_buf->head, &ctx->bo_list);
bo_node->as_mob = as_mob;
bo_node->cpu_blit = cpu_blit;
Fails the same BUG_ON with num_fences and max_fences == 0.
Thanks for testing this.
So the buffer object is not reserved through
vmw_validation_bo_reserve(), but comes from somewhere else.
Unfortunately I absolutely can't find where that's coming from.
Do you have some documentation howto setup vmwgfx? E.g. sample VM
which
I can download somewhere etc..
I don't have an external machine to upload it to. Getting an external
machine to run Mesa CI on has been on our todo for a while, so I'll try
to setup something next week.
The issue here seems to be that vmwgfx always had some buffers that
didn't immediately go through vmw_validation_bo_reserve. What's
happening is that in vmwgfx_execbuf.c in vmw_execbuf_process we call
vmw_validation_bo_reserve and after it we call
vmw_validation_res_validate. Inside vmw_validation_res_validate (in
vmwgfx_validation.c) we call vmw_resource_validate, which calls
vmw_resource_do_validate . vmw_resource_do_validate has this code "ret
= func->create(res);" which is an issue for vmwgfx_cotable.c . The
func->create for cotable's is vmw_cotable_create which calls
vmw_cotable_resize which creates, reserves and validates a new bo.
Just wow! No wonder that I missed that, I would have never ever been
able to find it.
In short a new bo is created in vmw_cotable_resize between
ttm_eu_reserve_buffers and ttm_eu_fence_buffer_objects calls.
Well then the fix is trivial, we just need to call
dma_resv_reserve_fences() on this new BO to make sure that at least one
fence slot is reserved.
I will try to come up with a patch. Thanks a lot for that!
Regards,
Christian.
z
