parisc: led: Reduce CPU overhead for disk & lan LED computation

Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

kernel os linux

Older PA-RISC machines have LEDs which show the disk- and LAN-activity.
The computation is done in software and takes quite some time, e.g. on a
J6500 this may take up to 60% time of one CPU if the machine is loaded
via network traffic.

Since most people don't care about the LEDs, start with LEDs disabled and
just show a CPU heartbeat LED. The disk and LAN LEDs can be turned on
manually via /proc/pdc/led.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>

Helge Deller 2 years ago 358ad816 8f01caf0

+2 -2

1 changed file

expand all

drivers

parisc

led.c

+2 -2

drivers/parisc/led.c

··· 56 56 static int led_type __read_mostly = -1; 57 57 static unsigned char lastleds; /* LED state from most recent update */ 58 58 static unsigned int led_heartbeat __read_mostly = 1; 59 - static unsigned int led_diskio __read_mostly = 1; 60 - static unsigned int led_lanrxtx __read_mostly = 1; 59 + static unsigned int led_diskio __read_mostly; 60 + static unsigned int led_lanrxtx __read_mostly; 61 61 static char lcd_text[32] __read_mostly; 62 62 static char lcd_text_default[32] __read_mostly; 63 63 static int lcd_no_led_support __read_mostly = 0; /* KittyHawk doesn't support LED on its LCD */