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I have written a driver for linux to communicate with /dev/fb0. When system boots, The LCD turns on and displays random colors, but when startx runs (that I expect desktop environment to be shown), LCD turns off and after a while this error is claimed through UART log:

cpufreq: __cpufreq_driver_target: Failed to change cpu frequency: -16

cpufreq_cpu0: failed to set clock rate: -16

what is the problem?

closed as too broad by Rui F Ribeiro, RalfFriedl, Thomas Dickey, DarkHeart, Archemar Sep 16 '18 at 7:10

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • Consider ask this on stackoverflow, and post the minimal code. – 炸鱼薯条德里克 Sep 16 '18 at 9:12
  • @神秘德里克 what code is helpful? just tel and I will post anything that can be help :) – Mojtaba Ahmadi Sep 16 '18 at 9:15
  • stackoverflow, I think that would be a better place for this question. Since you're writing a kernel driver, maybe some error related code is needed to identify your error. I'm not expert in kernel development, just suggesting you to re-post this to a might be more proper community. – 炸鱼薯条德里克 Sep 16 '18 at 9:21
  • @神秘德里克 aha, ok, tnx – Mojtaba Ahmadi Sep 16 '18 at 9:23