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drm: avoid "possible bad bitmask?" warning

Message ID 1470764110-23855-1-git-send-email-david.s.gordon@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dave Gordon Aug. 9, 2016, 5:35 p.m. UTC
Recent versions of gcc say this:

include/drm/i915_drm.h:96:34: warning: result of ‘65535 << 20’
requires 37 bits to represent, but ‘int’ only has 32 bits
[-Wshift-overflow=]

Reported-by: David Binderman <linuxdev.baldrick@gmail.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Cc: Dave Airlie <airlied@gmail.com>
---
 include/drm/i915_drm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Chris Wilson Aug. 9, 2016, 7:53 p.m. UTC | #1
On Tue, Aug 09, 2016 at 06:35:10PM +0100, Dave Gordon wrote:
> Recent versions of gcc say this:
> 
> include/drm/i915_drm.h:96:34: warning: result of ‘65535 << 20’
> requires 37 bits to represent, but ‘int’ only has 32 bits
> [-Wshift-overflow=]
> 
> Reported-by: David Binderman <linuxdev.baldrick@gmail.com>
> Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
> Cc: Dave Airlie <airlied@gmail.com>
> ---
>  include/drm/i915_drm.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
> index b1755f8..4e1b274 100644
> --- a/include/drm/i915_drm.h
> +++ b/include/drm/i915_drm.h
> @@ -93,6 +93,6 @@ extern bool i915_gpu_turbo_disable(void);
>  #define    I845_TSEG_SIZE_1M	(3 << 1)
>  
>  #define INTEL_BSM 0x5c
> -#define   INTEL_BSM_MASK (0xFFFF << 20)
> +#define   INTEL_BSM_MASK	(-(1u << 20))

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris
Daniel Vetter Aug. 9, 2016, 8:18 p.m. UTC | #2
On Tue, Aug 9, 2016 at 9:53 PM, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> On Tue, Aug 09, 2016 at 06:35:10PM +0100, Dave Gordon wrote:
>> Recent versions of gcc say this:
>>
>> include/drm/i915_drm.h:96:34: warning: result of ‘65535 << 20’
>> requires 37 bits to represent, but ‘int’ only has 32 bits
>> [-Wshift-overflow=]
>>
>> Reported-by: David Binderman <linuxdev.baldrick@gmail.com>
>> Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
>> Cc: Dave Airlie <airlied@gmail.com>
>> ---
>>  include/drm/i915_drm.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
>> index b1755f8..4e1b274 100644
>> --- a/include/drm/i915_drm.h
>> +++ b/include/drm/i915_drm.h
>> @@ -93,6 +93,6 @@ extern bool i915_gpu_turbo_disable(void);
>>  #define    I845_TSEG_SIZE_1M (3 << 1)
>>
>>  #define INTEL_BSM 0x5c
>> -#define   INTEL_BSM_MASK (0xFFFF << 20)
>> +#define   INTEL_BSM_MASK     (-(1u << 20))
>
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

And applied, thanks.
-Daniel
diff mbox

Patch

diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index b1755f8..4e1b274 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -93,6 +93,6 @@  extern bool i915_gpu_turbo_disable(void);
 #define    I845_TSEG_SIZE_1M	(3 << 1)
 
 #define INTEL_BSM 0x5c
-#define   INTEL_BSM_MASK (0xFFFF << 20)
+#define   INTEL_BSM_MASK	(-(1u << 20))
 
 #endif				/* _I915_DRM_H_ */