Cannot edit /sys/devices config file as root

slkuser · 07-24-2016, 09:52 AM

Hey guys,

Specs: Scientific Linux 6 / 64-bit

I am attempting to resolve a 'boot freeze' with a clocksource failover complaint according to a fix on RHLE and here https://blog.remibergsma.com/2012/03...-system-crash/...Consiting of editing the current system clock:

$su
$echo "acpi_pm" > /sys/devices/system/clocksource/clocksource0/current_clocksource

The issue I am encountering is that echo can't edit the current_clocksource config file. I attempted a text editor to no avail.

Any help I could get would be much appreciated.

keefaz · 07-24-2016, 11:53 AM

This is a virtual file (exists only on memory).
Does it return something?

Code:

cat /sys/devices/system/clocksource/clocksource0/current_clocksource

Echo will not edit this "file" but it will send a write command (by the shell) to a kernel handler which will do the appropriate action

slkuser · 07-24-2016, 02:30 PM

Thanks for the clarification. Yes it does:

$ cat /sys/devices/system/clocksource/clocksource0/current_clocksource
> tsc

keefaz · 07-24-2016, 04:25 PM

And acpi_pm is available?

Code:

cat /sys/devices/system/clocksource/clocksource0/available_clocksource

slkuser · 07-25-2016, 08:28 AM

I don't think so. The idea was to set it up, via the echo write above.

$cat /sys/devices/system/clocksource/clocksource0/available_clocksource
> tsc jiffies

Quote:

Originally Posted by keefaz

And acpi_pm is available?

Code:

cat /sys/devices/system/clocksource/clocksource0/available_clocksource