Re: [PATCH v2] macintosh/via-pmu-led: make disk activity usage a parameter.
From: Nathan Lynch <hidden>
Date: 2021-10-26 13:08:52
Also in:
linuxppc-dev, lkml
Hello, Hill Ma [off-list ref] writes:
Whether to use the LED as a disk activity is a user preference. Some like this usage while others find the LED too bright. So it might be a good idea to make this choice a runtime parameter rather than compile-time config.
Users already have the ability to change the LED behavior at runtime already, correct? I.e. they can do: echo none > /sys/class/leds/pmu-led::front/trigger in their boot scripts. Granted, a kernel built with ADB_PMU_LED_DISK=y will blink the LED on disk activity until user space is running. Is this unsatisfactory?
The default is set to disabled as OS X does not use the LED as a disk activity indicator.
This is long-standing behavior in Linux and OS X has been EOL on this architecture for a decade, so this isn't much of a consideration at this point. Seems more important to avoid surprising existing users and distributions with a behavior change that makes additional work for them. See below.
quoted hunk ↗ jump to hunk
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 43dc35fe5bc0..a656a51ba0a8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt@@ -250,6 +250,12 @@ Use timer override. For some broken Nvidia NF5 boards that require a timer override, but don't have HPET + adb_pmu_led_disk [PPC] + Use front LED as disk LED by default. Only applies to + PowerBook, iBook, PowerMac 7,2/7,3. + Format: <bool> (1/Y/y=enable, 0/N/n=disable) + Default: disabled + add_efi_memmap [EFI; X86] Include EFI memory map in kernel's map of available physical RAM.diff --git a/drivers/macintosh/Kconfig b/drivers/macintosh/Kconfig index 5cdc361da37c..243215de563c 100644 --- a/drivers/macintosh/Kconfig +++ b/drivers/macintosh/Kconfig@@ -78,16 +78,6 @@ config ADB_PMU_LED behaviour of the old CONFIG_BLK_DEV_IDE_PMAC_BLINK, select this and the disk LED trigger and configure appropriately through sysfs. -config ADB_PMU_LED_DISK - bool "Use front LED as DISK LED by default" - depends on ADB_PMU_LED - depends on LEDS_CLASS - select LEDS_TRIGGERS - select LEDS_TRIGGER_DISK - help - This option makes the front LED default to the disk trigger - so that it blinks on disk activity. -
So, if I've been relying on CONFIG_ADB_PMU_LED_DISK=y and I upgrade to a newer kernel with the proposed change, from my point of view the disk activity LED has stopped working and I need to alter the bootloader config or init scripts to restore the expected behavior. That seems undesirable to me. I don't think we rigidly enforce Kconfig backward compatibility, but when it comes to a user-visible function on a legacy platform where users and distros likely have their configurations figured out already, it's probably best to avoid such changes.