[PATCH/RFC v2 0/2] CPUFreq for kzm9g
From: Guennadi Liakhovetski <hidden>
Date: 2013-03-01 21:11:41
Also in:
linux-sh
On Tue, 26 Feb 2013, Magnus Damm wrote:
On Tue, Feb 26, 2013 at 2:16 AM, Guennadi Liakhovetski [off-list ref] wrote:quoted
In v2 of this patch-set I dropped patches 1 and 3, because #1 is a bug-fix and can go in separately, #3 is more of a debugging help, than a real patch for mainlining. Of the remaining 2 patches the main difference to v1 is the omission of the PLL0 manipulation. More is explained in respective patches. Guennadi Liakhovetski (2): ARM: shmobile: sh73a0: add support for adjusting CPU frequency ARM: shmobile: kzm9g-reference: add CPUFreq supportHi Guennadi, Thanks for your work on this. In general I am quite happy about this series. One rather significant question is however this: Would it be possible for you to check if the TWD is operating as expected when you scale the CPU Frequency? I suspect it is not, so please cook up a v3 of this series that also includes updates for timers.
At last I managed to get twd running with a recent (of 27.02) all+next snapshot on kzm9g with DT (reference) and actually I'm not really sure the problem is there. At least definitely not as bad as I saw it last time. To remind, the problem I observed was, that at lower CPU speeds a simple shell script, consisting of 20 20-second sleep calls was gaining multiple seconds, was taking more like 405 seconds, than 400. Now I only see it going to 401 seconds. This is still not good, but I need a more precise comparison to actually decide, whether this problem only appears at lower CPU speeds or it is always there. I'll look further into it next week. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/