[PATCH] ARM: vfp: fix fpsid register subarchitecture field mask width

Will Deacon will.deacon at arm.com
Fri Feb 22 13:27:06 EST 2013


Hi guys,

On Fri, Feb 22, 2013 at 08:08:05AM +0000, Stephen Boyd wrote:
> From: Steve Muckle <smuckle at codeaurora.org>
> 
> The subarchitecture field in the fpsid register is 7 bits wide.
> The topmost bit is used to designate that the subarchitecture
> designer is not ARM. We use this field to determine which VFP
> version is supported by the CPU. Since the topmost bit is masked
> off we detect non-ARM subarchitectures as supporting only
> HWCAP_VFP and not HWCAP_VFPv3 as it should be for Qualcomm's
> processors.

I'm struggling to see why this has anything to do with the hwcaps being set
incorrectly. What value do you have in fpsid? As far as I can tell, the
subarchitecture bits 6:0 should start at 0x40 for you, right?

I can see cases for changing this code, I just don't see why it would go
wrong in the case you're describing.

Cheers,

Will



More information about the linux-arm-kernel mailing list