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From: "Christian König" <christian.koenig@amd.com>
To: Arnd Bergmann <arnd@arndb.de>, Jammy Zhou <Jammy.Zhou@amd.com>,
	David Airlie <airlied@linux.ie>
Cc: Eric Huang <JinHuiEric.Huang@amd.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	David Zhang <david1.zhang@amd.com>
Subject: Re: [PATCH] drm: powerplay: use div64_s64 instead of do_div
Date: Mon, 4 Jan 2016 13:48:25 +0100	[thread overview]
Message-ID: <568A6A19.7060309@amd.com> (raw)
In-Reply-To: <5249276.tkZ1gbxakA@wuerfel>

On 01.01.2016 14:07, Arnd Bergmann wrote:
> The newly added code for Fiji creates a correct compiler warning
> about invalid use of the do_div macro:
>
> In file included from powerplay/hwmgr/ppatomctrl.c:31:0:
> drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h: In function 'fDivide':
> drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h:382:89: warning: comparison of distinct pointer types lacks a cast
>       do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
>
> do_div() divides an unsigned 64-bit number by an unsigned 32-bit number.
> The code instead wants to divide two signed 64-bit numbers, which is done
> using the div64_s64 function.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Christian König <christian.koenig@amd.com>

> Fixes: 770911a3cfbb ("drm/amd/powerplay: add/update headers for Fiji SMU and DPM")
> ---
> Found on ARM allmodconfig on yesterday's linux-next
>
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
> index 42f2423cddea..411cb0fcdf98 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
> @@ -379,7 +379,7 @@ fInt fDivide (fInt X, fInt Y)
>   
>       longlongX = longlongX << 16; /*Q(16,16) -> Q(32,32) */
>   
> -    do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
> +    div64_s64(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
>   
>       fQuotient.full = (int)longlongX;
>       return fQuotient;
>

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WARNING: multiple messages have this Message-ID (diff)
From: "Christian König" <christian.koenig@amd.com>
To: Arnd Bergmann <arnd@arndb.de>, Jammy Zhou <Jammy.Zhou@amd.com>,
	"David Airlie" <airlied@linux.ie>
Cc: Eric Huang <JinHuiEric.Huang@amd.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	David Zhang <david1.zhang@amd.com>,
	<linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH] drm: powerplay: use div64_s64 instead of do_div
Date: Mon, 4 Jan 2016 13:48:25 +0100	[thread overview]
Message-ID: <568A6A19.7060309@amd.com> (raw)
In-Reply-To: <5249276.tkZ1gbxakA@wuerfel>

On 01.01.2016 14:07, Arnd Bergmann wrote:
> The newly added code for Fiji creates a correct compiler warning
> about invalid use of the do_div macro:
>
> In file included from powerplay/hwmgr/ppatomctrl.c:31:0:
> drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h: In function 'fDivide':
> drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppevvmath.h:382:89: warning: comparison of distinct pointer types lacks a cast
>       do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
>
> do_div() divides an unsigned 64-bit number by an unsigned 32-bit number.
> The code instead wants to divide two signed 64-bit numbers, which is done
> using the div64_s64 function.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Christian König <christian.koenig@amd.com>

> Fixes: 770911a3cfbb ("drm/amd/powerplay: add/update headers for Fiji SMU and DPM")
> ---
> Found on ARM allmodconfig on yesterday's linux-next
>
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
> index 42f2423cddea..411cb0fcdf98 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/ppevvmath.h
> @@ -379,7 +379,7 @@ fInt fDivide (fInt X, fInt Y)
>   
>       longlongX = longlongX << 16; /*Q(16,16) -> Q(32,32) */
>   
> -    do_div(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
> +    div64_s64(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
>   
>       fQuotient.full = (int)longlongX;
>       return fQuotient;
>


  parent reply	other threads:[~2016-01-04 12:48 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-01 13:07 [PATCH] drm: powerplay: use div64_s64 instead of do_div Arnd Bergmann
2016-01-01 13:07 ` Arnd Bergmann
2016-01-04  8:17 ` Thierry Reding
2016-01-04  8:17   ` Thierry Reding
2016-01-04 12:48 ` Christian König [this message]
2016-01-04 12:48   ` Christian König
2016-01-04 15:42 ` Alex Deucher
2016-01-04 15:42   ` Alex Deucher

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