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Wed, 08 Oct 2025 15:00:18 -0700 (PDT) Received: from [192.168.1.12] ([41.37.1.171]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4255d8e9762sm32013820f8f.38.2025.10.08.15.00.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Oct 2025 15:00:18 -0700 (PDT) Message-ID: Date: Thu, 9 Oct 2025 01:00:16 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RESEND] drm/amd/display: Initialize return value in dm_cache_state() To: Mario Limonciello , Harry Wentland , Leo Li , Rodrigo Siqueira , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= , David Airlie , Simona Vetter , Alex Hung , Wayne Lin , Aurabindo Pillai , Tom Chung , Dominik Kaszewski , Yilin Chen , "open list:AMD DISPLAY CORE" , "open list:DRM DRIVERS" , open list References: <20251007224549.87548-1-eslam.medhat1993@gmail.com> <6f24d0cb-ce14-4e56-990b-00ad579bc282@amd.com> Content-Language: en-US From: Eslam Khafagy In-Reply-To: <6f24d0cb-ce14-4e56-990b-00ad579bc282@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Thu, 09 Oct 2025 07:45:21 +0000 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On 10/8/25 05:15, Mario Limonciello wrote: > > > On 10/7/2025 5:45 PM, Eslam Khafagy wrote: >> Initialize the return variable "r" to 0 in dm_cache_state() to fix >> a potential use of uninitialized variable warning. >> >> The return value for this function might not be a PTR_ERR, in casse if >> condition fails. In that case we ensure predictable reutrn. > > Can you walk me through your thought process?  I looked at all > possible returns for drm_atomic_helper_suspend() and they all return > ERR_PTR() or a state. > > So I don't see how the IS_ERR() clause could have a problem. Hello , Thank you for the response. Initially i was working on warnings via coverity scan. Initially my thinking was just by following the sequence of dm_cache_state you can see that there was a potential issue if drm_atomic_helper_suspend returned a non valid pointer that is not PTR_ERR. But having a second look after your response, indeed it shouldn't be the case. so please feel free to drop this patch. >> >> Signed-off-by: Eslam Khafagy >> --- >>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +- >>   1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >> index 8e1622bf7a42..6b4f3eb9ce48 100644 >> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >> @@ -3115,7 +3115,7 @@ static void hpd_rx_irq_work_suspend(struct >> amdgpu_display_manager *dm) >>     static int dm_cache_state(struct amdgpu_device *adev) >>   { >> -    int r; >> +    int r = 0; >>         adev->dm.cached_state = >> drm_atomic_helper_suspend(adev_to_drm(adev)); >>       if (IS_ERR(adev->dm.cached_state)) { >