Re: [PATCH 2/5] VT binding: Add sysfs support

Greg KH wrote:

On Sat, Jun 10, 2006 at 08:38:18AM +0800, Antonino A. Daplas wrote:

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Greg KH wrote:

quoted

On Fri, Jun 09, 2006 at 04:39:51PM +0800, Antonino A. Daplas wrote:

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Add sysfs attributes for binding and unbinding VT console drivers. The
attributes are located in /sys/class/tty/console and are namely:

    A. backend - list registered drivers in the following format:

    "I C: Description"

No, this violates the "one value per file" issue with sysfs.  How do you
know you will not overflow the buffer passed to you?

I was wondering about this. I just want a way to show what are the currently
loaded drivers, so it's a read-only attribute.  It's using snprintf (though
I haven't added a check for possible overflows, should be a 2-liner). Maximum
number of lines is 16, and there are examples of this rule-breakage in the
current sysfs tree.

/sys/class/usb_host/usb_hostx/device/pools

Ah, thanks for pointing this out.  Those files should go to debugfs,
they do NOT belong in sysfs at all.

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Yes, none are valid excuses.  Anyway, what would be the best way? I was
considering creating another class for vt_console, but that would entail
the creation of a new device major number just for this.

No, you don't need a major to create a new class in sysfs at all.  Look
at usb_host for an example of that :)

Aha, I see it now. Yes, this is exactly what I need. Thanks for the tip.

Ok, I also read the 0/5 in this series which describes this in detail,
sorry for not seeing that (hint, cc: everyone on the series that one
too, so they get a bit of detail in the future.)

Sorry about that, slipped my mind.

Tony