2023-10-30 17:27:15

by José Pekkarinen

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Subject: [PATCH] drm/amd/display: remove redundant check

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: [email protected]
Signed-off-by: José Pekkarinen <[email protected]>
---
.../drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
index ecea008f19d3..d940dfa5ae43 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
@@ -4661,10 +4661,6 @@ void dml32_CalculateMinAndMaxPrefetchMode(
} else if (AllowForPStateChangeOrStutterInVBlankFinal == dm_prefetch_support_uclk_fclk_and_stutter) {
*MinPrefetchMode = 0;
*MaxPrefetchMode = 0;
- } else if (AllowForPStateChangeOrStutterInVBlankFinal ==
- dm_prefetch_support_uclk_fclk_and_stutter_if_possible) {
- *MinPrefetchMode = 0;
- *MaxPrefetchMode = 3;
} else {
*MinPrefetchMode = 0;
*MaxPrefetchMode = 3;
--
2.39.2


2023-10-30 17:39:49

by Aurabindo Pillai

[permalink] [raw]
Subject: Re: [PATCH] drm/amd/display: remove redundant check



On 2023-10-30 13:17, 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: [email protected]
> Signed-off-by: José Pekkarinen <[email protected]>
> ---
> .../drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
> index ecea008f19d3..d940dfa5ae43 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
> +++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c
> @@ -4661,10 +4661,6 @@ void dml32_CalculateMinAndMaxPrefetchMode(
> } else if (AllowForPStateChangeOrStutterInVBlankFinal == dm_prefetch_support_uclk_fclk_and_stutter) {
> *MinPrefetchMode = 0;
> *MaxPrefetchMode = 0;
> - } else if (AllowForPStateChangeOrStutterInVBlankFinal ==
> - dm_prefetch_support_uclk_fclk_and_stutter_if_possible) {
> - *MinPrefetchMode = 0;
> - *MaxPrefetchMode = 3;
> } else {
> *MinPrefetchMode = 0;
> *MaxPrefetchMode = 3;

Reviewed-by: Aurabindo Pillai <[email protected]>

2023-10-31 05:48:45

by Greg Kroah-Hartman

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Subject: Re: [PATCH] drm/amd/display: remove redundant check

On Mon, Oct 30, 2023 at 07:17:48PM +0200, Jos? 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: [email protected]

Why is this relevant for stable?

2023-10-31 12:20:36

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH] drm/amd/display: remove redundant check

On Tue, Oct 31, 2023 at 01:42:17PM +0200, Jos? Pekkarinen wrote:
> On 2023-10-31 07:48, Greg KH wrote:
> > On Mon, Oct 30, 2023 at 07:17:48PM +0200, Jos? 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: [email protected]
> >
> > 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?

thanks,

greg k-h

2023-10-31 12:32:27

by José Pekkarinen

[permalink] [raw]
Subject: Re: [PATCH] drm/amd/display: remove redundant check

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: [email protected]
>> >
>> > 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.

2023-10-31 15:21:03

by José Pekkarinen

[permalink] [raw]
Subject: Re: [PATCH] drm/amd/display: remove redundant check

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: [email protected]
>
> 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

Feel free to let me know if this is wrong, or if I
need to review some other guidelines I may have missed.

Thanks!

José.

2023-10-31 16:42:48

by Aurabindo Pillai

[permalink] [raw]
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: [email protected]
>>> >
>>> > 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.