struct fb_ops functions and sleeping

struct fb_ops functions and sleeping

[Ondrej Zajicek]

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Hello

I would like to ask whether there are any rules about context in which
functions from struct fb_ops are called, particularly whether they can
sleep and which functions may be called only between some fb_open
and fb_release (for example from fbcon).

I tried to get working two graphics cards using VGA arbiter patch
(http://www.ussg.iu.edu/hypermail/linux/kernel/0503.1/0054.html)
After some hacking it worked, but without proper locking.

-- 
Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago@mail.cz, jabber: santiago@njs.netlab.cz)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."

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Re: struct fb_ops functions and sleeping

[Antonino A. Daplas]

Ondrej Zajicek wrote:
> Hello
> 
> I would like to ask whether there are any rules about context in which
> functions from struct fb_ops are called, particularly whether they can
> sleep

Most of the functions can be called in process context (can sleep), except
in some unlikely cases (printing an oops).

Of all the functions in there, make sure that fb_blank() cannot sleep.

 and which functions may be called only between some fb_open
> and fb_release (for example from fbcon).

It's guaranteed that none of the functions will get called before
an fb_open() or after a successful fb_release().

Tony


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