On 9/10/2026 3:15 PM, Jiqian Chen wrote:
> isp_suspend() and isp_resume() return -ENODEV when the ISP version does
> not implement the optional hw_suspend()/hw_resume() callbacks. Only
> isp_v4_1_1_funcs provides them, isp_v4_1_0_funcs defines just hw_init and
> hw_fini, so on ISP v4.1.0 both callbacks are NULL and every system
> suspend and resume fails.
>
> amdgpu_ip_block_suspend() and amdgpu_ip_block_resume() treat an error
> returned by the IP block as fatal, so this aborts the whole amdgpu
> suspend/resume, for example:
>
> amdgpu 0000:c5:00.0: amdgpu: resume of IP block <isp_ip> failed -19
>
> Because amdgpu_ip_block_resume() bails out before updating the state,
> ip_block->status.hw is left stale and the GPU is only partially resumed,
> which also breaks subsequent suspend cycles.
>
> An absent callback means there is nothing to do, not an error. This is
> how the IP block core itself treats a NULL amd_ip_funcs entry, it skips
> the call and reports success. Return 0 in that case so ISP versions
> without suspend/resume callbacks no longer break device suspend/resume.
>
> Fixes: 7ed51e3a1381 ("drm/amd/amdgpu: Fix SMU warning during isp
> suspend-resume")
> Signed-off-by: Jiqian Chen <[email protected]>
Reviewed-by: Bin Du <[email protected]>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_isp.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_isp.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_isp.c
> index 976b65f90bc1..ad667b9fde84 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_isp.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_isp.c
> @@ -321,7 +321,7 @@ static int isp_resume(struct amdgpu_ip_block *ip_block)
> if (isp->funcs->hw_resume)
> return isp->funcs->hw_resume(isp);
>
> - return -ENODEV;
> + return 0;
> }
>
> static int isp_suspend(struct amdgpu_ip_block *ip_block)
> @@ -332,7 +332,7 @@ static int isp_suspend(struct amdgpu_ip_block *ip_block)
> if (isp->funcs->hw_suspend)
> return isp->funcs->hw_suspend(isp);
>
> - return -ENODEV;
> + return 0;
> }
>
> static const struct amd_ip_funcs isp_ip_funcs = {
