Hi Thiago, On Wed, 2010-08-18 at 18:16 +0200, ext Thiago Macieira wrote: > On Wednesday 18 August 2010 15:09:37 Arjan van de Ven wrote: > > On 8/18/2010 3:19 AM, Carsten Munk wrote: > > > [this is not another SSSE3 discussion thread] > > > > > > Qt on OMAP3 has very big benefits from using NEON, just like using > > > SSSE3 does on Atom. However, we do not currently compile for NEON in > > > MeeGo for ARMv7 as not all ARMv7 has NEON (Marvell, Nvidia being > > > notable exceptions). > > > > > > We'd obviously like to use NEON on Nokia N900 but we're wondering how > > > to do this in the most ecosystem-friendly way. > > > > > > I have been talking to Thiago and he mentions that an environment > > > variable QT_NO_NEON=1 exists to disable NEON usage by Qt. > > > > > > So, my proposal is the following: > > > > > > Compile Qt with NEON support by default on ARMv7. Include script in > > > startup that provides QT_NO_NEON=1 to the UX session based on NEON > > > presence in /proc/cpuinfo. > > > > couldn't QT read /proc/cpuinfo (or do the equivalent of cpuid) instead > > of looking for the env variable? > > I don't know how the kernel detects the presence of the Neon coprocessor. But > looking at ARM documentation doesn't show any instruction for cpuid. In > general, for embedded devices, you don't need cpuid since "you know what you > put in your device". > > The kernel also passes the CPU capabilities to the process in the auxv, but > that is not exposed anywhere outside ld.so.
How about "/proc/self/auxv"? Cheers, Ameya. _______________________________________________ MeeGo-dev mailing list [email protected] http://lists.meego.com/listinfo/meego-dev
