Re: [PATCH for review] ACPI: Create /sys/firmware/acpi/interrupts/ counters

Greg KH
2008-02-05T23:23:00Z

On Tue, Feb 05, 2008 at 06:12:09PM -0500, Len Brown wrote:
> On Tuesday 05 February 2008 17:18, Greg KH wrote:
> > On Tue, Feb 05, 2008 at 02:30:10AM -0500, Len Brown wrote:
> > > # cat /sys/firmware/acpi/interrupts/summary
> > > pm_timer 0
> > > glbl_lock 0
> > > power_btn 0
> > > sleep_btn 0
> > > rtc 0
> > > gpe00 0
> ...
> > > gpe1F 0
> > > gpe_hi 0
> > > gpe_total 63
> > > acpi_irq 63
> >
> > Eeek! Why? What's wrong with individual files here?
>
> My expectation is that this is a shell interface for debugging,
> not an API for programs. ala /proc/interrupts.

Great, then use debugfs for it. Please, don't put debug stuff like this
in sysfs, that's not what it is there for. You can do whatever you want
in debugfs :)

> if we have 40 individual files, each with a number in it,
> it is less convenient to cat the file and paste the results
> into an email or bug report and have the receiver easily
> see what what count goes with what file -- or is there
> a version of cat that prints the file name before
> the contents of each file?
>
> I've seen
> more * | cat
> but one has to wonder why an interface would be built
> to make something so simple not be simple.

Use debugfs please.

> > What's to ensure
> > that you aren't going to overflow your buffer?
>
> Good question. What's to ensure we don't overflow it
> when I print any other random string?
> Who allocates it and how big is it?

The core does, and if you are putting something too big in it, you are
using the sysfs interface wrong :)

Simple, one value per file is what sysfs is for. Use debugfs for
debugging stuff.

thanks,

greg k-h