[PATCH] drm/amdgpu: fix SI failure due to doorbells allocation

[Alex Deucher]

Applied.  Thanks!

On Mon, Oct 9, 2023 at 5:27 AM Sharma, Shashank <Shashank.Sharma at amd.com> wrote:
>
> [AMD Official Use Only - General]
>
> Reviewed-by: Shashank Sharma <shashank.sharma at amd.com>
>
> Regards
> Shashank
> -----Original Message-----
> From: Icenowy Zheng <uwu at icenowy.me>
> Sent: Sunday, October 8, 2023 8:47 AM
> To: Deucher, Alexander <Alexander.Deucher at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Pan, Xinhui <Xinhui.Pan at amd.com>; David Airlie <airlied at gmail.com>; Daniel Vetter <daniel at ffwll.ch>; Sharma, Shashank <Shashank.Sharma at amd.com>; Yadav, Arvind <Arvind.Yadav at amd.com>
> Cc: amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org; linux-kernel at vger.kernel.org; Icenowy Zheng <uwu at icenowy.me>
> Subject: [PATCH] drm/amdgpu: fix SI failure due to doorbells allocation
>
> SI hardware does not have doorbells at all, however currently the code will try to do the allocation and thus fail, makes SI AMDGPU not usable.
>
> Fix this failure by skipping doorbells allocation when doorbells count is zero.
>
> Fixes: 54c30d2a8def ("drm/amdgpu: create kernel doorbell pages")
> Signed-off-by: Icenowy Zheng <uwu at icenowy.me>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> index d0249ada91d30..599aece42017a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> @@ -142,6 +142,10 @@ int amdgpu_doorbell_create_kernel_doorbells(struct amdgpu_device *adev)
>         int r;
>         int size;
>
> +       /* SI HW does not have doorbells, skip allocation */
> +       if (adev->doorbell.num_kernel_doorbells == 0)
> +               return 0;
> +
>         /* Reserve first num_kernel_doorbells (page-aligned) for kernel ops */
>         size = ALIGN(adev->doorbell.num_kernel_doorbells * sizeof(u32), PAGE_SIZE);
>
> --
> 2.39.1
>