linux-kernel - Re: [PATCH 5/7] drm/amd/display: Use proper enum conversion functions

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Date:   Thu, 25 Jul 2019 16:14:25 +0000
From:   "Kazlauskas, Nicholas" <Nicholas.Kazlauskas@....com>
To:     "Li, Sun peng (Leo)" <Sunpeng.Li@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>,
        "Zhou, David(ChunMing)" <David1.Zhou@....com>,
        "Wentland, Harry" <Harry.Wentland@....com>,
        Rex Zhu <rex.zhu@....com>, "Quan, Evan" <Evan.Quan@....com>
CC:     David Airlie <airlied@...ux.ie>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "clang-built-linux@...glegroups.com" 
        <clang-built-linux@...glegroups.com>,
        "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
        Nathan Chancellor <natechancellor@...il.com>
Subject: Re: [PATCH 5/7] drm/amd/display: Use proper enum conversion functions

On 7/25/19 12:00 PM, Li, Sun peng (Leo) wrote:
> 
> 
> On 2019-07-18 11:16 p.m., Nathan Chancellor wrote:
>> On Wed, Jul 03, 2019 at 10:52:16PM -0700, Nathan Chancellor wrote:
>>> clang warns:
>>>
>>> drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_pp_smu.c:336:8:
>>> warning: implicit conversion from enumeration type 'enum smu_clk_type'
>>> to different enumeration type 'enum amd_pp_clock_type'
>>> [-Wenum-conversion]
>>>                                          dc_to_smu_clock_type(clk_type),
>>>                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_pp_smu.c:421:14:
>>> warning: implicit conversion from enumeration type 'enum
>>> amd_pp_clock_type' to different enumeration type 'enum smu_clk_type'
>>> [-Wenum-conversion]
>>>                                          dc_to_pp_clock_type(clk_type),
>>>                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> There are functions to properly convert between all of these types, use
>>> them so there are no longer any warnings.
>>>
>>> Fixes: a43913ea50a5 ("drm/amd/powerplay: add function get_clock_by_type_with_latency for navi10")
>>> Fixes: e5e4e22391c2 ("drm/amd/powerplay: add interface to get clock by type with latency for display (v2)")
>>> Link: https://github.com/ClangBuiltLinux/linux/issues/586
>>> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
>>> ---
>>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c | 4 ++--
>>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c
>>> index eac09bfe3be2..0f76cfff9d9b 100644
>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c
>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c
>>> @@ -333,7 +333,7 @@ bool dm_pp_get_clock_levels_by_type(
>>>   		}
>>>   	} else if (adev->smu.funcs && adev->smu.funcs->get_clock_by_type) {
>>>   		if (smu_get_clock_by_type(&adev->smu,
>>> -					  dc_to_smu_clock_type(clk_type),
>>> +					  dc_to_pp_clock_type(clk_type),
> 
> smu_funcs->get_clock_by_type doesn't seem to be hooked up anywhere,
> so this looks to be the most correct.
> 
> Although it makes more sense to use smu_clk_types here rather than
> amd_pp_clock_type - any reason why this isn't the case?
> 
>>>   					  &pp_clks)) {
>>>   			get_default_clock_levels(clk_type, dc_clks);
>>>   			return true;
>>> @@ -418,7 +418,7 @@ bool dm_pp_get_clock_levels_by_type_with_latency(
>>>   			return false;
>>>   	} else if (adev->smu.ppt_funcs && adev->smu.ppt_funcs->get_clock_by_type_with_latency) {
>>>   		if (smu_get_clock_by_type_with_latency(&adev->smu,
>>> -						       dc_to_pp_clock_type(clk_type),
>>> +						       dc_to_smu_clock_type(clk_type),
> 
> This is slightly concerning. The functions are doing the right thing,
> but amd_pp_clock_type doesn't map 1-1 to smu_clk_type... In any case,
> this looks good to me.
> 
> Reviewed-by: Leo Li <sunpeng.li@....com>

Looks mostly like the table just needs to be sized properly:

	static int dc_clk_type_map[] = {
->
	static int dc_clk_type_map[DM_PP_CLOCK_TYPE_NUM_TYPES] = {

where DM_PP_CLOCK_TYPE_NUM_TYPES would be added to enum dm_pp_clock_type.

Or it could just use a switch table instead, like the other function does.

Nicholas Kazlauskas

> 
>>>   						       &pp_clks))
>>>   			return false;
>>>   	}
>>> -- 
>>> 2.22.0
>>>
>>
>> Gentle ping for review, this is the last remaining warning that I see
>> from amdgpu on next-20190718.
>>
>> Cheers,
>> Nathan
>>
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> dri-devel@...ts.freedesktop.org
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