Andrew Murray had written, on 01/26/2010 02:34 PM, the following:
Hello,
With regards to the OMAP2 (or at least the 3530 EVM) -the TRM and
various whitepapers suggest that they are 3 OPP levels available for
VDD2 (L3). However, from looking at the sources (linux-omap-pm / pm
branch) it seems that only 2 OPP levels are supported (@166Mhz and
@83Mhz) and used. I also notice that these rates are different to those
in a whitepaper (166, 100 and 41.5). Is there any particular reason why
on OMAP34/35xx, I believe it should be s/100/83/.
only 2 OPPs are used?
to my knowledge 41.5Mhz is not known to provide any performance
benefits. you can also see [1] and add 41.5 (pm-wip-opp is the new
branch where we are introducing opp layer.
I understand that the OPP level of VDD2 may be set by changes to the OPP
level of VDD1 (i.e. resource34xx.c:set_opp) - and modifying VDD1's OPP
via cpufreq seems to be the only way to adjust the VDD2 OPP from
user-land - is this correct?
The old /sys/power/vdd2_[opp|lock] was deprecated out. currently the
control is for vdd1 OPP using cpufreq and indirect dependency for VDD2,
is there a need for direct control of VDD2 freq?
--
Regards,
Nishanth Menon
Ref:
[1]
http://git.kernel.org/?p=linux/kernel/git/khilman/linux-omap-pm.git;a=blob;f=arch/arm/mach-omap2/cpufreq34xx.c;h=07873e87ffc0fef97b4554efc3f17dc696cb25e3;hb=4f54a09e0ed9b2ee8e1adfe1716297792310d1c6#l46
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
