Content-Type: multipart/alternative; boundary=Apple-Mail-7-437292315 --Apple-Mail-7-437292315 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 I think that is a good idea to have a default u-boot variable for CPU = frequency of 500MHz, so that it's a lot easier for a user to find what = needs to be changed to bump the frequency if they desire. Cheers, Kai On 05/09/2010, at 9:25 PM, S=F8ren Steen Christensen wrote: > I have now checked at TI E2E, and TI said/confirmed (as I expected), = that it=92s the voltage more than the frequency which age the chips =3D> = 600MHz and 720MHz are both considered overdrive modes for both 600- and = 720-grade silicon. Please see answer here: = https://e2e.ti.com/support/dsp/omap_applications_processors/f/447/p/62063/= 223487.aspx#223487=20 >=20 > The highest totally safe operating freq (100K POH) is therefore 500MHz = regardless of chip-grade. Increasing to 600MHz or 720MHz will = statistically shorten the chip lifetime (and increase the power = consumption), so I recommend keeping default at 500MHz, but it might be = an idea to introduce a dummy mpurate variable set to 500 in U-boot for = users to easily figure out what to change in order to increase the speed = to i.e. 600MHz or 720 MHz should the need/want. > =20 > The above being said. The complete idea with OMAP is to run at as low = a frequency as possible when not needing the processing power and just = scale to something higher on the fly when needed. In the longer run I = therefore think it=92s best to just let Linux = idle-thread/frequency-governor handle the CPU scaling (with a user = defined max-setting). There is already some support for this, but to be = honest I haven=92t checked it for a long time=85 > =20 > Best regards and thanks =96 I hope this clarified the topic? > S=F8ren > =20 > --- > SSC Solutions ApS - Denmark - www.ssc-solutions.dk > = --------------------------------------------------------------------------= ---- > This SF.net Dev2Dev email is sponsored by: >=20 > Show off your parallel programming skills. > Enter the Intel(R) Threading Challenge 2010. > = http://p.sf.net/sfu/intel-thread-sfd______________________________________= _________ > gumstix-users mailing list > gumstix-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/gumstix-users --Apple-Mail-7-437292315 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 I think that is a good idea to have a default = u-boot variable for CPU frequency of 500MHz, so that it's a lot easier = for a user to find what needs to be changed to bump the frequency if = they = desire.

Cheers,
Kai

O= n 05/09/2010, at 9:25 PM, S=F8ren Steen Christensen wrote:

I = have now checked at TI E2E, and TI said/confirmed (as I expected), that = it=92s the voltage more than the frequency which age the chips =3D> = 600MHz and 720MHz are both considered overdrive modes for both 600- and = 720-grade silicon. Please see answer here: https://e2e.ti.com/support/dsp/omap_applications_processors/f/447/p/6206= 3/223487.aspx#223487 

The highest = totally safe operating freq (100K POH) is therefore 500MHz regardless of = chip-grade. Increasing to 600MHz or 720MHz will statistically shorten = the chip lifetime (and increase the power consumption), so I recommend = keeping default at 500MHz, but it might be an idea to introduce a dummy = mpurate variable set to 500 in U-boot for users to easily figure out = what to change in order to increase the speed to i.e. 600MHz or 720 MHz = should the need/want.
The above being said. The complete idea with OMAP is = to run at as low a frequency as possible when not needing the processing = power and just scale to something higher on the fly when needed. In the = longer run I therefore think it=92s best to just let Linux = idle-thread/frequency-governor handle the CPU scaling (with a user = defined max-setting). There is already some support for this, but to be = honest I haven=92t checked it for a long = time=85
 
Best regards and thanks = =96 I hope this clarified the topic?
  = S=F8ren
 
SSC Solutions ApS - Denmark = - www.ssc-solutions.dk SF.net Dev2Dev email is sponsored = by:

Show off your parallel programming skills.
Enter the = Intel(R) Threading Challenge 2010.