2021-12-08 07:46:31

by CGEL

Subject: [PATCH linux-next] drm/i915/display: Delete redundant post_mask assignment

From: luo penghao <[email protected]>

This value will be overwritten by the following if statement, even
if the if is not executed, the value will not be used

The clang_analyzer complains as follows:

Value stored to 'port_mask' is never read

Reported-by: Zeal Robot <[email protected]>
Signed-off-by: luo penghao <[email protected]>
---
drivers/gpu/drm/i915/display/intel_ddi.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index bd18432..3aad0c3 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -2011,7 +2011,6 @@ void intel_ddi_sanitize_encoder_pll_mapping(struct intel_encoder *encoder)
return;
}

- port_mask = BIT(encoder->port);
ddi_clk_needed = encoder->base.crtc;

if (encoder->type == INTEL_OUTPUT_DSI) {
--
2.15.2

2021-12-08 13:04:23

by Ville Syrjälä

Subject: Re: [PATCH linux-next] drm/i915/display: Delete redundant post_mask assignment

On Wed, Dec 08, 2021 at 07:46:19AM +0000, [email protected] wrote:
> From: luo penghao <[email protected]>
>
> This value will be overwritten by the following if statement, even
> if the if is not executed, the value will not be used
>
> The clang_analyzer complains as follows:
>
> Value stored to 'port_mask' is never read
>
> Reported-by: Zeal Robot <[email protected]>
> Signed-off-by: luo penghao <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index bd18432..3aad0c3 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -2011,7 +2011,6 @@ void intel_ddi_sanitize_encoder_pll_mapping(struct intel_encoder *encoder)
> return;
> }
>
> - port_mask = BIT(encoder->port);
> ddi_clk_needed = encoder->base.crtc;
>
> if (encoder->type == INTEL_OUTPUT_DSI) {

'port_mask' declaration could now be moved into this block.

> --
> 2.15.2
>

--
Ville Syrj?l?
Intel

2021-12-08 13:20:24

by Jani Nikula

Subject: Re: [PATCH linux-next] drm/i915/display: Delete redundant post_mask assignment

On Wed, 08 Dec 2021, Ville Syrjälä <[email protected]> wrote:
> On Wed, Dec 08, 2021 at 07:46:19AM +0000, [email protected] wrote:
>> From: luo penghao <[email protected]>
>>
>> This value will be overwritten by the following if statement, even
>> if the if is not executed, the value will not be used
>>
>> The clang_analyzer complains as follows:
>>
>> Value stored to 'port_mask' is never read
>>
>> Reported-by: Zeal Robot <[email protected]>
>> Signed-off-by: luo penghao <[email protected]>
>> ---
>> drivers/gpu/drm/i915/display/intel_ddi.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
>> index bd18432..3aad0c3 100644
>> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
>> @@ -2011,7 +2011,6 @@ void intel_ddi_sanitize_encoder_pll_mapping(struct intel_encoder *encoder)
>> return;
>> }
>>
>> - port_mask = BIT(encoder->port);
>> ddi_clk_needed = encoder->base.crtc;
>>
>> if (encoder->type == INTEL_OUTPUT_DSI) {
>
> 'port_mask' declaration could now be moved into this block.

I've basically given up on patches from [email protected],
[email protected], [email protected], etc. The patches are the
simplest possible changes to silence static analyzer warnings, with no
further analysis of the issues, and no follow-up on questions.

Until that changes, I think we're better off just regarding them static
as analyzer reports.


BR,
Jani.


>
>> --
>> 2.15.2
>>

--
Jani Nikula, Intel Open Source Graphics Center