On Tue, 29 Aug 2017, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, Aug 01, 2017 at 02:53:43PM +0530, Viresh Kumar wrote: >> Users must be given an option to discard any constraints set by >> bootloaders. For example, consider that a constraint is set for the LCD >> controller's supply and the LCD driver isn't loaded by the kernel. If >> the user doesn't need to use the LCD device, then he shouldn't be forced >> to honour the constraint. >> >> We can also think about finer control of such constraints with help of >> some sysfs files, but a kernel parameter is fine to begin with. >> >> Tested-by: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx> >> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx> >> --- >> Documentation/admin-guide/kernel-parameters.txt | 3 +++ >> drivers/base/boot_constraints/core.c | 17 +++++++++++++++++ >> 2 files changed, 20 insertions(+) >> >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt >> index d9c171ce4190..0706d1b6004d 100644 >> --- a/Documentation/admin-guide/kernel-parameters.txt >> +++ b/Documentation/admin-guide/kernel-parameters.txt >> @@ -426,6 +426,9 @@ >> embedded devices based on command line input. >> See Documentation/block/cmdline-partition.txt >> >> + boot_constraints_disable >> + Do not set any boot constraints for devices. > > Shouldn't that be the default? As really, that is what the situation is > today, why force everyone to always enable the disable value? And > enabling a value to disable something is usually a sign of bad naming... > >> + >> boot_delay= Milliseconds to delay each printk during boot. >> Values larger than 10 seconds (10000) are changed to >> no delay (0). >> diff --git a/drivers/base/boot_constraints/core.c b/drivers/base/boot_constraints/core.c >> index 366a05d6d9ba..e0c33b2b216f 100644 >> --- a/drivers/base/boot_constraints/core.c >> +++ b/drivers/base/boot_constraints/core.c >> @@ -24,6 +24,17 @@ >> static LIST_HEAD(constraint_devices); >> static DEFINE_MUTEX(constraint_devices_mutex); >> >> +static bool boot_constraints_disabled; > > Again, this should only be an "enable" type of option, that kicks in if > you are using this type of bootloader/kernel interaction. Don't force > someone to disable it. I might add that "disable" type options lead to annoying double negatives. Regardless of the default, I'd generally prefer "enable" type options that you enable/disable as needed. BR, Jani. -- Jani Nikula, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
