topic I can't change the CPU frequency on the fly in i.MX Processors https://community.nxp.com/t5/i-MX-Processors/I-can-t-change-the-CPU-frequency-on-the-fly/m-p/194784#M10211 <HTML><HEAD></HEAD><BODY><P>Hi all:</P><P>&nbsp; I can't change the CPU frequency on the fly on mx28evk board, and in the Reference Manual document it tells us it is OK.</P></BODY></HTML> Tue, 13 Dec 2011 22:52:51 GMT alex 2011-12-13T22:52:51Z I can't change the CPU frequency on the fly https://community.nxp.com/t5/i-MX-Processors/I-can-t-change-the-CPU-frequency-on-the-fly/m-p/194784#M10211 <HTML><HEAD></HEAD><BODY><P>Hi all:</P><P>&nbsp; I can't change the CPU frequency on the fly on mx28evk board, and in the Reference Manual document it tells us it is OK.</P></BODY></HTML> Tue, 13 Dec 2011 22:52:51 GMT https://community.nxp.com/t5/i-MX-Processors/I-can-t-change-the-CPU-frequency-on-the-fly/m-p/194784#M10211 alex 2011-12-13T22:52:51Z Re: I can't change the CPU frequency on the fly https://community.nxp.com/t5/i-MX-Processors/I-can-t-change-the-CPU-frequency-on-the-fly/m-p/194785#M10212 <HTML><HEAD></HEAD><BODY><P>I have same problem here either. It seems like iMX28 Linux cpufreq driver</P><P>has serious bug.</P><P></P><P>The reference manual says</P><P>echo 392727 &gt; /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed</P><P>will change the CPU frequency, but the board just locks up.</P><P>(392727 should not be a supported frequency for iMX28 -</P><P>cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state shows</P><P>261818, 360000 and 454736 as supported frequency. Anyway, setting</P><P>other than 454736 to scaling_setspeed causes lock-up).</P><P></P><P>My EVK is iMX28 EVK Rev.D, using Linux SDHC memory came with the EVK; uname -a shows</P><P>Linux freescale 2.6.31-855-ge067785 #1 Fri Sep 10 09:22:06 MDT 2010 armv5tejl GNU/Linux</P><P></P><P>Google search shows same issue was reported on forum back on Jul 2011.</P><P><A href="http://imxcommunity.org/forum/topics/imx28-change-the-cpu?commentId=4103961%3AComment%3A34105&amp;xg_source=activity" target="_blank">http://imxcommunity.org/forum/topics/imx28-change-the-cpu?commentId=4103961%3AComment%3A34105&amp;xg_source=activity</A></P><P>Even though patch is provided from Freescale, it was reported it didn't fix the problem.</P></BODY></HTML> Fri, 06 Jan 2012 02:25:45 GMT https://community.nxp.com/t5/i-MX-Processors/I-can-t-change-the-CPU-frequency-on-the-fly/m-p/194785#M10212 YS 2012-01-06T02:25:45Z