linux-kernel - Re: [PATCH] drm/amd/display: remove redundant check

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Message-ID: <9f50181b-15da-44b3-9620-4d3e1e1d8557@amd.com>
Date:   Tue, 31 Oct 2023 12:41:16 -0400
From:   Aurabindo Pillai <aurabindo.pillai@....com>
To:     José Pekkarinen <jose.pekkarinen@...hound.fi>,
        Greg KH <gregkh@...uxfoundation.org>
Cc:     harry.wentland@....com, sunpeng.li@....com,
        Rodrigo.Siqueira@....com, skhan@...uxfoundation.org,
        dillon.varone@....com,
        linux-kernel-mentees@...ts.linuxfoundation.org,
        dri-devel@...ts.freedesktop.org, Xinhui.Pan@....com,
        linux-kernel@...r.kernel.org, samson.tam@....com,
        SyedSaaem.Rizvi@....com, stable@...r.kernel.org, daniel@...ll.ch,
        george.shen@....com, alexander.deucher@....com, Jun.Lei@....com,
        airlied@...il.com, christian.koenig@....com
Subject: Re: [PATCH] drm/amd/display: remove redundant check



On 2023-10-31 08:32, José Pekkarinen wrote:
> On 2023-10-31 14:20, Greg KH wrote:
>> On Tue, Oct 31, 2023 at 01:42:17PM +0200, José Pekkarinen wrote:
>>> On 2023-10-31 07:48, Greg KH wrote:
>>> > On Mon, Oct 30, 2023 at 07:17:48PM +0200, José Pekkarinen wrote:
>>> > > This patch addresses the following warning spotted by
>>> > > using coccinelle where the case checked does the same
>>> > > than the else case.
>>> > >
>>> > > 
>>> drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c:4664:8-10:
>>> > > WARNING: possible condition with no effect (if == else)
>>> > >
>>> > > Fixes: 974ce181 ("drm/amd/display: Add check for PState change in
>>> > > DCN32")
>>> > >
>>> > > Cc: stable@...r.kernel.org
>>> >
>>> > Why is this relevant for stable?
>>>
>>>     Hi,
>>>
>>>     I was asked to send it for stable because this code
>>> looks different in amd-staging-drm-next, see here.
>>>
>>> https://gitlab.freedesktop.org/agd5f/linux/-/blob/amd-staging-drm-next/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c#L4661
>>
>> I don't know what I am looking at, sorry.
>>
>>>     Feel free to let me know if this is wrong, or if I
>>> need to review some other guidelines I may have missed.
>>
>> Please see the list of rules for stable patches:
>> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
>>
>> Does "remove code that does nothing" fit here?
> 
>      Yep, it is a trivial fix which compilers should be able
> to optimize, so no real benefit to the user. Sorry Greg!
> 
>      José.

Hi Greg,

Sorry, I asked José to send it to stable because I realized the patch 
listed in the fixes tag wasnt quite needed on stable. Patch from José 
effectively removes it.

I hope that clears the context. But there is no impact whether you apply 
José's patch or not, so we're good either way.