Bug 30718 - evergreen.c bad cast/shift
Summary: evergreen.c bad cast/shift
Status: RESOLVED FIXED
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Radeon (show other bugs)
Version: unspecified
Hardware: Other Linux (All)
: medium normal
Assignee: Default DRI bug account
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Reported: 2010-10-08 17:01 UTC by Dave Gilbert
Modified: 2010-10-11 09:42 UTC (History)
0 users

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Description Dave Gilbert 2010-10-08 17:01:37 UTC 
Hi,
  Sparse spotted the following and it does look like the wrong order of cast and shift:


drivers/gpu/drm/radeon/evergreen.c:1140:78: warning: right shift by bigger than source value


                efuse_box_bit_127_124 = (u8)(efuse_straps_3 & 0xF0000000) >> 28;

I think I agree with it that in that the value is truncated to u8 before being
shifted down by 28 and therefore always being 0. So easiest fix I guess is:

                efuse_box_bit_127_124 = (u8)((efuse_straps_3 & 0xF0000000) >>28);

Not sure what the effect of this would be, it seems to be in some very device specific code.

Dave
Comment 1 Alex Deucher 2010-10-11 09:42:42 UTC 
good catch.  I've sent Dave a patch:
http://lists.freedesktop.org/archives/dri-devel/2010-October/004705.html
Thanks!

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