linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2006-07-31	[CPUFREQ] return error when failing to set minfreq	Mattia Dongili	1	-1/+4
	I just stumbled on this bug/feature, this is how to reproduce it: # echo 450000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq # echo 450000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq # echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor # cpufreq-info -p 450000 450000 powersave # echo 1800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq ; echo $? 0 # cpufreq-info -p 450000 450000 powersave Here it is. The kernel refuses to set a min_freq higher than the max_freq but it allows a max_freq lower than min_freq (lowering min_freq also). This behaviour is pretty straightforward (but undocumented) and it doesn't return an error altough failing to accomplish the requested action (set min_freq). The problem (IMO) is basically that userspace is not allowed to set a full policy atomically while the kernel always does that thus it must enforce an ordering on operations. The attached patch returns -EINVAL if trying to increase frequencies starting from scaling_min_freq and documents the correct ordering of writes. Signed-off-by: Mattia Dongili <malattia@linux.it> Signed-off-by: Dominik Brodowski <linux at dominikbrodowski.net> Signed-off-by: Dave Jones <davej@redhat.com> --
2005-04-16	Linux-2.6.12-rc2	Linus Torvalds	1	-0/+185
	Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!