linux-kernel - Re: [PATCH linux-next] drm/amdgpu/vcn: Remove unused assignment in vcn_v4_0

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Date:   Mon, 15 Aug 2022 21:53:54 +0600
From:   Khalid Masum <khalid.masum.92@...il.com>
To:     "Dong, Ruijing" <Ruijing.Dong@....com>,
        "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-kernel-mentees@...ts.linuxfoundation.org" 
        <linux-kernel-mentees@...ts.linuxfoundation.org>
Cc:     "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "Zhu, James" <James.Zhu@....com>,
        "Jiang, Sonny" <Sonny.Jiang@....com>,
        Wan Jiabing <wanjiabing@...o.com>, "Liu, Leo" <Leo.Liu@....com>
Subject: Re: [PATCH linux-next] drm/amdgpu/vcn: Remove unused assignment in
 vcn_v4_0_stop

On 8/15/22 21:17, Dong, Ruijing wrote:
> [AMD Official Use Only - General]
> 
> If the condition was met and it came to execute vcn_4_0_stop_dpg_mode, then it would never have a chance to go for /*wait for vcn idle*/, isn't it?

Hypothetically, some other thread might set adev->pg_flags NULL and in 
that case it will get the chance to go for /* wait for vcn idle */.


> I still didn't see obvious purpose of this change.
> 
>                  if (adev->pg_flags & AMD_PG_SUPPORT_VCN_DPG) {
>       ==>              r = vcn_v4_0_stop_dpg_mode(adev, i);

Regardless of that, this assignment to r is unnecessary. Because this 
value of r is never used. This patch simply removes this unnecessary
assignment.

>                           continue;
>                   }
> 
>                   /* wait for vcn idle */
>                   r = SOC15_WAIT_ON_RREG(VCN, i, regUVD_STATUS, UVD_STATUS__IDLE, 0x7);
> 
> Thanks
> Ruijing
> 

Thanks,
   -- Khalid Masum