Re: 回复: Re: [PATCH libdrm 1/2] amdgpu: fix parameter of amdgpu_cs_ctx_create2

["Christian König" <christian.koenig@amd.com>]

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Am 09.01.24 um 02:50 schrieb 李真能:
>
> When the priority value is passed to the kernel, the kernel compares 
> it with the following values:
>
> #define AMDGPU_CTX_PRIORITY_VERY_LOW    -1023
> #define AMDGPU_CTX_PRIORITY_LOW         -512
> #define AMDGPU_CTX_PRIORITY_NORMAL      0
> #define AMDGPU_CTX_PRIORITY_HIGH        512
> #define AMDGPU_CTX_PRIORITY_VERY_HIGH   1023
>
> If priority is uint32_t, we can't set LOW and VERY_LOW value to kernel 
> context priority,
>

Well that's nonsense.

How the kernel handles the values and how userspace handles them are two 
separate things. You just need to make sure that it's always 32 bits.

In other words if you have signed or unsigned data type in userspace is 
irrelevant for the kernel.

> You can refer to the kernel function amdgpu_ctx_priority_permit, if 
> priority is greater
>
> than 0, and this process has not  CAP_SYS_NICE capibility or 
> DRM_MASTER permission,
>
> this process will be exited.
>

Correct, that's intentional.

Regards,
Christian.

>
>
>
>
>
> ----
>
>
>
>
> *主　题：*Re: [PATCH libdrm 1/2] amdgpu: fix parameter of 
> amdgpu_cs_ctx_create2
> *日　期：*2024-01-09 00:28
> *发件人：*Christian König
> *收件人：*李真能;Marek Olsak;Pierre-Eric Pelloux-Prayer;dri-devel;amd-gfx;
>
> Am 08.01.24 um 10:40 schrieb Zhenneng Li:
> > In order to pass the correct priority parameter to the kernel,
> > we must change priority type from uint32_t to int32_t.
>
> Hui what? Why should it matter if the parameter is signed or not?
>
> That doesn't seem to make sense.
>
> Regards,
> Christian.
>
> >
> > Signed-off-by: Zhenneng Li
> > ---
> > amdgpu/amdgpu.h | 2 +-
> > amdgpu/amdgpu_cs.c | 2 +-
> > 2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/amdgpu/amdgpu.h b/amdgpu/amdgpu.h
> > index 9bdbf366..f46753f3 100644
> > --- a/amdgpu/amdgpu.h
> > +++ b/amdgpu/amdgpu.h
> > @@ -896,7 +896,7 @@ int amdgpu_bo_list_update(amdgpu_bo_list_handle 
> handle,
> > *
> > */
> > int amdgpu_cs_ctx_create2(amdgpu_device_handle dev,
> > - uint32_t priority,
> > + int32_t priority,
> > amdgpu_context_handle *context);
> > /**
> > * Create GPU execution Context
> > diff --git a/amdgpu/amdgpu_cs.c b/amdgpu/amdgpu_cs.c
> > index 49fc16c3..eb72c638 100644
> > --- a/amdgpu/amdgpu_cs.c
> > +++ b/amdgpu/amdgpu_cs.c
> > @@ -49,7 +49,7 @@ static int 
> amdgpu_cs_reset_sem(amdgpu_semaphore_handle sem);
> > * \return 0 on success otherwise POSIX Error code
> > */
> > drm_public int amdgpu_cs_ctx_create2(amdgpu_device_handle dev,
> > - uint32_t priority,
> > + int32_t priority,
> > amdgpu_context_handle *context)
> > {
> > struct amdgpu_context *gpu_context;
>

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