-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Somebody in the thread at some point said:
| I put together a cpuidle driver for the S3C2410 and added the | NO_HZ/clockevents work from Andresz to my build. What follows is a | list of time spent in idle (that's S3C2410 mode IDLE) for my GTA01. | Some of the long idle times are really impressive (almost 0.5 | seconds). ... | Anyway, the point of this post is to see what is happening in | powersaving work. I had a look at adding an idle-mode that switches | to SLOW mode; this might be feasible, but as so many drivers need to | adjust to the change of clock rate, the time to enter and leave this | idle mode becomes significant (although, for 0.5 seconds, it should be | no problem). Thanks for looking at this area. 500mS chunks in SLOW or some strong powersaving mode wth short wakes before the next one is pretty serious potential powersaving. | That said, there is no support for clock rate adjustment at all right | now. Is somebody working on this or does this already work in | somebody's tree somewhere? Cesar has cpufreq patches for GTA01, Ben Dooks mentioned them by name when I met him and he seemed interested to take them upstream. I saw the odd cpufreq reference in s3c arch stuff in stable-tracking, but when I went to grep it I see they are not really doing anything yet. | I think we need to adjust the 'clk' infrastructure so that: | i) Children are notified when parent clock rate changes | ii) Clocks can be reparented (for example, for SLOW mode we switch | from MPLL to XTAL). | iii) Clocks get a list of callbacks to invoke when their rate changes | so that drivers can make the necessary adjustments. (e.g. framebuffer | driver needs to know when hclk changes in order to adjust its vclk | divider) I cc Ben and Cesar. - -Andy -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iEYEARECAAYFAkkHylIACgkQOjLpvpq7dMqm4ACfdu1aRLNCImtxTBgBftwiZkJW XH4An1f7vRt975L7253g9Kseu9zNLRQ6 =Krn7 -----END PGP SIGNATURE-----
